Helicopter Engine-Rotor System Compatibility
This SAE Aerospace Recommended Practice (ARP) recommends a methodology to be used for the design, analysis and test evaluation of modern helicopter gas turbine propulsion system stability and transient response characteristics.
This methodology utilizes the computational power of modern digital computers to more thoroughly analyze, simulate and bench-test the helicopter engine/rotor system speed control loop over the flight envelope. This up-front work results in significantly less effort expended during flight test and delivers a more effective system into service.
The methodology presented herein is recommended for modern digital electronic propulsion control systems and also for traditional analog and hydromechanical systems.
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Version 1 - 2026-06-22
These Terms and Conditions (the “Terms”) consist of four parts that together form a single, integrated agreement governing access to the Nimonik Online Store and the purchase and use of Products from Nimonik:
Part A — Terms and Conditions of Sale, which governs the purchase of the Product;
Part B — End Customer Licence Agreement, which governs the use of the Product;
Part C — Use of the Website and Account, which governs use of the Nimonik Online Store and applies to all users, whether or not a purchase is made; and
Part D — General Terms, which applies to Parts A, B, and C.
By placing an order for, or accessing, downloading, printing, installing, or otherwise using, a Product or the Nimonik Online Store, you accept and agree to be bound by these Terms.
The following definitions apply throughout this document, including Part A and Part B:
”Nimonik” means Document Center Inc., a California corporation, with its registered office at 401 Roland Way, Ste#224, Oakland, CA, 94621, United States.
”Nimonik Online Store” means Nimonik’s online standards store at https://standards.nimonik.com, through which Products are offered, ordered, accessed, and delivered.
”Licensee” or “you” means the purchaser or end-user of the Product.
”Product” means the standard, publication, document, or other content supplied by Nimonik, whether in electronic format or in hard-copy printed format. Any reference to the Product includes the Product in its entirety or any part thereof, as applicable.
”Owner” means the copyright holder of the Product identified on or within the Product.
”Licence Fee” means the amount paid by the Licensee for the Product.
”T&Cs” means the Terms and Conditions of Sale set out in Part A.
These T&Cs govern the purchase of Products by the Licensee from Nimonik.
By placing an order for a Product, or by accessing, downloading, installing, or otherwise using the Product, the Licensee accepts and agrees to be bound by these T&Cs and by the End Customer Licence Agreement set out in Part B. The Licensee shall ensure that it has read and understood all applicable terms before completing the purchase.
Any questions regarding these Terms may be addressed to Nimonik via https://standards-nimonik.freshdesk.com/support/tickets/new
The Licensee shall pay the applicable price for the Product. Once a card payment has been processed, an invoice confirming the payment will be emailed to the Licensee. Orders are paid by credit card and are charged in full at the time the order is placed.
Where invoice payment has been approved by Nimonik in writing, an invoice will be issued for payment in accordance with the following terms:
Payment is due in full within thirty (30) days of the invoice date, unless otherwise agreed in writing by Nimonik.
Payments must be made in U.S. Dollars (USD) and include the relevant order number.
Nimonik may accrue interest on overdue amounts at the rate of 1.5% per month, or the maximum rate permitted by applicable law, whichever is lower, calculated from the due date until paid in full. The Licensee shall be responsible for all reasonable costs of collection, including legal fees.
Nimonik may suspend or withhold delivery of, or access to, any Product until all overdue amounts have been paid in full.
The Licensee is responsible for all bank charges, transfer fees, and foreign exchange risks associated with the payment. The Licensee is also responsible for any local taxes, customs duties, or other charges imposed by the destination jurisdiction.
Sales tax is applied to orders with a billing address in any U.S. state where Nimonik is required to collect such tax. Applicable sales or use tax is determined based on the Licensee’s billing or delivery address.
All orders placed through the Nimonik Online Store constitute an offer to purchase and are subject to acceptance by Nimonik. Nimonik may, in its sole discretion, refuse, limit, or cancel any order, or any quantity ordered, at any time prior to fulfilment, for any reason it deems appropriate.
Nimonik uses reasonable efforts to ensure that prices and product information displayed on the Nimonik Online Store are accurate. However, errors may occur. Nimonik reserves the right to correct any errors, inaccuracies, or omissions, and to change or update prices and information at any time without prior notice. In the event a Product is listed at an incorrect price or with incorrect information due to a typographical or other error, Nimonik may, at its discretion, cancel or refuse any order placed for that Product, whether or not the order has been confirmed and payment processed. If payment has already been taken for a cancelled order, Nimonik will issue a full refund of the amount charged.
Products are made available only in one of two formats:
in electronic format, accessible for authenticated users via the Nimonik Online Store, as either a downloadable PDF or a view-only PDF (depending on the digital rights management (DRM) requirements applicable to the Product), or
in hard-copy printed format, dispatched either from Nimonik’s facility in the United States or directly by the publisher or Owner of the Product, depending on the Product.
No other formats are offered.
Products are made available/dispatched once the order has been processed.
Any delivery times, dispatch times, or shipping estimates shown in the Nimonik Online Store or at checkout are approximate and provided for guidance only. Actual delivery times may vary and depend on a range of factors, including order processing, payment clearance, product format, carrier performance, destination, customs handling, and other circumstances beyond Nimonik’s reasonable control. Nimonik does not guarantee any specific delivery or dispatch date and shall not be liable for any delay in delivery.
Returns are not accepted for electronic Products (PDF).
Returns of hard-copy Products may be accepted only in cases of duplicate orders or, on an exceptional basis, on a case-by-case assessment. In all instances, returns are subject to Nimonik’s prior agreement and must follow the procedure specified by Nimonik.
For termination of the use rights, please refer to the End Customer Licence Agreement in Part B.
Nimonik processes personal data provided in connection with an order in accordance with applicable data protection laws, and only as necessary to process the order, deliver the Product, and meet its legal obligations.
For both hard-copy and electronic Products, license rights apply to the content of the Products. Content of Products is made available under licence, as further specified in the End Customer Licence Agreement (Part B), and not sold.
Products are protected by copyright law and other applicable laws. Use of Products, including permitted use, restrictions, intellectual property rights, compliance obligations, and termination, is governed exclusively by the End Customer Licence Agreement.
In the event of any inconsistency, the End Customer Licence Agreement shall prevail with respect to the use of Products.
TO THE MAXIMUM EXTENT PERMITTED BY LAW, THE PRODUCTS ARE PROVIDED “AS IS” AND “AS AVAILABLE,” AND ARE SOLD AND LICENSED WITHOUT ANY REPRESENTATION OR WARRANTY OF ANY KIND, WHETHER EXPRESS, IMPLIED, OR STATUTORY, INCLUDING WITHOUT LIMITATION ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, ACCURACY, OR NON-INFRINGEMENT.
TO THE MAXIMUM EXTENT PERMITTED BY LAW, NIMONIK SHALL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, EXEMPLARY, OR PUNITIVE DAMAGES, OR FOR ANY LOSS OF PROFITS, REVENUE, DATA, OR GOODWILL, ARISING OUT OF OR IN CONNECTION WITH THESE T&Cs OR THE PURCHASE OR USE OF ANY PRODUCT, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
NIMONIK’S TOTAL AGGREGATE LIABILITY ARISING OUT OF OR IN CONNECTION WITH THESE T&Cs OR ANY PRODUCT SHALL NOT EXCEED THE AMOUNT ACTUALLY PAID BY THE LICENSEE FOR THE PRODUCT GIVING RISE TO THE CLAIM. NOTHING IN THESE T&Cs EXCLUDES OR LIMITS LIABILITY THAT CANNOT BE EXCLUDED OR LIMITED UNDER APPLICABLE LAW, INCLUDING LIABILITY FOR DAMAGE CAUSED BY GROSS NEGLIGENCE OR INTENT.
IMPORTANT — READ CAREFULLY BEFORE DOWNLOADING, PRINTING, ACCESSING, OR OTHERWISE USING THE PRODUCT.
This agreement (the “Agreement”) sets out the terms on which the Licensee may use the Product. This Agreement is entered into together with, and forms part of the same overall agreement as, the T&Cs.
By placing an order for a Product, or by accessing, downloading, printing, installing, or otherwise using the Product, the Licensee accepts and agrees to be bound by this Agreement and the T&Cs. The Licensee shall ensure that it has read and understood all applicable terms before completing the purchase.
Any questions regarding this Agreement may be addressed to Nimonik via https://standards-nimonik.freshdesk.com/support/tickets/new
This Agreement sets out the terms under which Nimonik grants the Licensee access to, and rights to use, the Product, whether in whole or in part.
The licence granted under this Agreement applies only to the specific edition of the Product purchased or downloaded by the Licensee. It does not include any previous or subsequent edition. Unless expressly agreed otherwise in writing, Nimonik does not provide document updates, maintenance, or support services for the Product.
(a) Subject to full payment of the applicable Licence Fee and the Licensee’s compliance with this Agreement, Nimonik grants the Licensee a non-exclusive, non-transferable, limited, and revocable licence to use the Product for use by a single named user. This Agreement does not convey to you any ownership interest in or to the content of the Product.
(b) Permitted use includes the right to access, read, consult, and internally reference the Product, and to understand, evaluate, and apply its content within the Licensee’s own internal operations, processes, and management systems.
(c) Where the Product is provided electronically as a downloadable PDF, the Licensee, as a single named user, may only access the Product as an authenticated user via the Licensee’s Nimonik Online Store account. Unless the watermark or notice on the PDF itself states otherwise, the Licensee may download and store one (1) copy on a single personal device for use by that single user, and may print one (1) copy of the Product for personal use.
Where the Product is provided as a view-only PDF, the Licensee, as a single named user, may access and view the Product online as an authenticated user through the Licensee’s Nimonik Online Store account, but may not download, store, print, or otherwise reproduce the Product.
In all cases, concurrent use by two or more users, and any access to or storage of the Product on shared systems, networks, intranets, or shared drives, is not permitted.
(d) For identification and rights-management purposes, electronic copies of the Product may be watermarked with the account information provided by the Licensee at the time of purchase, including the Licensee’s email address.
(e) Where the Product is provided in hard-copy form, photocopying or reproduction in any form is not permitted without Nimonik’s prior written authorization.
(f) You shall provide Nimonik or any designee of Nimonik with all information reasonably necessary to verify compliance with this Agreement, and shall use your best efforts to cooperate with Nimonik to assure compliance.
The Product is protected by copyright law, database rights, trademark law, unfair competition law, trade secret law, and other applicable laws. The Licensee acknowledges and agrees to respect the Owner’s intellectual property rights in the Product and shall refrain from any act that may infringe, misappropriate, or otherwise violate such rights.
All right, title, and interest in and to the Product, together with any updates, corrections, derivative works, or ancillary materials, and all intellectual property rights therein, are and shall remain with the Owner. Where a Product is supplied in physical form, ownership of that physical medium may transfer to the purchaser; however, all intellectual property rights in the content of the Product remain with the Owner. Nothing in this Agreement assigns, transfers, or grants the Licensee any intellectual property rights in the Product, except for the limited rights expressly set out herein.
If Nimonik or its licensors are no longer authorized to license a Product, or if a claim of infringement arises or in Nimonik’s opinion is likely to arise, Nimonik may withdraw access to the Product temporarily or permanently, and the Licensee shall promptly suspend or cease all use of such Product. Nimonik may also, in its sole discretion, discontinue or withdraw any Product.
(a) General prohibitions. The Licensee shall not: use the Product outside the scope of the licence granted under this Agreement; grant use or access rights to the Product to, or disclose the Product to, any third party; sell, lend, lease, reproduce, distribute, import, export, or otherwise commercially exploit the Product, in whole or in part; merge, adapt, translate, or modify the Product; remove or alter any proprietary notice or label on or within the Product; or assign or otherwise transfer ownership of the Product to any third party.
(b) Artificial intelligence and machine learning. Except under a separate written licence granted by Nimonik or the Owner, the Licensee shall not access, use, or process the Product for or in relation to any machine learning, artificial intelligence (AI), or analogous computational purpose. This restriction includes, without limitation:
training, fine-tuning, or evaluating language models, machine-learning systems, generative AI models, or similar models or systems;
embedding, prompting, querying, comparing, or otherwise enabling an AI or ML model or system to ingest, reproduce, restate, summarize, translate, reformulate, or generate outputs derived from the Product;
structured extraction, text and data mining, harvesting, or processing of the text, structure, logic, metadata, or other elements of the Product for model training, dataset creation, benchmarking, or automated knowledge extraction; or
any other activity intended to enable an AI or ML system to ingest, analyze, internalize, or generate content based on the Product.
The Licensee may not rely on any statutory text-and-data-mining or similar exception to justify AI- or ML-related use of the Product.
The Licensee shall maintain accurate, complete, and up-to-date records relevant to its use of the Product and its compliance with this Agreement. If Nimonik has reasonable grounds to believe that the Licensee is not complying with this Agreement, Nimonik may, upon written notice, conduct an audit or require that an audit be carried out by an independent third-party auditor, during normal business hours at the Licensee’s premises or through remote access, as appropriate. Any underpayment of Licence Fees identified through an audit shall be invoiced to the Licensee and paid in full; if the audit reveals an underpayment, the Licensee shall also bear the reasonable costs of the audit and reimburse Nimonik within thirty (30) days of written notice.
Where the Product or any login credentials, passwords, or access tokens are provided to the Licensee, the Licensee shall keep them confidential and shall not share them with any third party or unauthorized user. The Licensee’s confidentiality obligations shall survive the expiration or termination of this Agreement, and the return or destruction of copies of the Product shall not relieve the Licensee of its continuing obligation to prevent unauthorized disclosure.
(a) Nimonik warrants for your benefit alone that, unless disclosed in the Product to the contrary, Nimonik and the Owner can license the Product and all copyright and trademarks related thereto or therein.
(b) THE EXPRESS WARRANTIES SET FORTH IN THIS SECTION 7 CONSTITUTE THE ONLY WARRANTIES WITH RESPECT TO THE PRODUCT, AND NIMONIK AND THE OWNER MAKE NO OTHER REPRESENTATION OR WARRANTY OR CONDITION OF ANY KIND, WHETHER EXPRESS OR IMPLIED (EITHER IN FACT OR BY OPERATION OF LAW), WITH RESPECT TO ANY OF THE PRODUCT, INCLUDING, WITHOUT LIMITATION, WITH RESPECT TO THE SUFFICIENCY, ACCURACY, OR UTILIZATION OF, OR ANY INFORMATION OR OPINION CONTAINED OR REFLECTED IN, ANY OF THE PRODUCT. NIMONIK AND THE OWNER EXPRESSLY DISCLAIM ALL WARRANTIES OR CONDITIONS OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
The Owner, Nimonik, any agent, representative, publisher, or distributor of the Product, and any of their respective directors, officers, employees, agents, representatives, or members (the “Nimonik and Owner Indemnified Parties”) shall have no liability for, and you shall defend, indemnify, and hold each of the Nimonik and Owner Indemnified Parties harmless from and against, any claim, loss, demand, liability, obligation, and expense (including reasonable attorneys’ fees) based upon or arising out of any injury or damage, or any product liability claim, including but not limited to any personal or bodily injury or property damage, arising out of, pertaining to, or resulting in any way from the use or possession of any of the Product by you and/or any of your directors, officers, employees, representatives, agents, or contractors, or from any breach of this Agreement.
(a) Whether or not Nimonik or the Owner has been advised of their possibility, neither Nimonik nor the Owner nor any of their representatives, agents, directors, officers, employees, or members shall be liable, whether under contract, tort (including negligence), or otherwise, for any indirect, special, punitive, incidental, or consequential loss, damage, cost, or expense of any kind whatsoever and howsoever caused that may be suffered by you or any third party. You are responsible for the consequences of any use of any of the Product.
(b) If an allegation of infringement of third-party rights is made, or in Nimonik’s or the Owner’s opinion is likely to be made, with respect to any Product, Nimonik may, at its option and expense, (i) obtain for you the right to continue using the Product, (ii) modify or replace the Product so as to avoid the claim, or (iii) refund the Licence Fee. Nimonik shall have no liability if any claim would have been avoided except for your refusal to use a modified or replacement Product or to cease using the Product. This Section 9(b) states the entire liability of Nimonik and the Owner with respect to any infringement or alleged infringement of third-party rights.
(c) TO THE MAXIMUM EXTENT PERMITTED BY LAW, AND NOTWITHSTANDING ANYTHING TO THE CONTRARY IN THIS AGREEMENT, THE TOTAL AGGREGATE LIABILITY OF NIMONIK AND THE OWNER ARISING OUT OF OR IN CONNECTION WITH THIS AGREEMENT OR ANY PRODUCT SHALL NOT EXCEED THE LICENCE FEE PAID BY THE LICENSEE FOR THE PRODUCT GIVING RISE TO THE CLAIM. NOTHING IN THIS AGREEMENT EXCLUDES OR LIMITS LIABILITY THAT CANNOT BE EXCLUDED OR LIMITED UNDER APPLICABLE LAW, INCLUDING LIABILITY FOR DAMAGE CAUSED BY GROSS NEGLIGENCE OR INTENT.
This licence is granted only for the edition of the Product confirmed in Nimonik’s order confirmation and does not grant any rights to revisions or new editions of the Product. This Agreement may be terminated immediately by the Owner or Nimonik upon breach of any provision by you. Upon any expiration or termination of this Agreement, you shall immediately discontinue all use of the Product and shall, within ten (10) days, either return any hard-copy Product to Nimonik or certify in writing to Nimonik that all electronic copies of the Product (including any printed copy and any backup copy) have been permanently deleted from your devices and eliminated from your premises. Provisions that by their nature are intended to survive termination shall so survive.
You may not load, export, or re-export any of the Product, or any underlying information or technology, except in full compliance with all United States and other applicable laws and regulations.
BY ACCESSING, DOWNLOADING, PRINTING, OR OTHERWISE USING THE PRODUCT, YOU ACKNOWLEDGE THAT YOU HAVE READ THE TERMS OF THIS LICENCE AGREEMENT AND AGREE TO BE BOUND BY ITS TERMS.
This section applies to everyone who accesses or uses the Nimonik Online Store, whether or not a purchase is made. In this section, “you” means any such user.
Account. You must provide accurate and complete information when registering for an account and keep it up to date. You are responsible for keeping your account credentials confidential and for all activity that occurs under your account. Accounts are personal to a single user and may not be shared. You must notify Nimonik promptly of any unauthorized use of your account. Nimonik may suspend or terminate an account at any time for breach of these Terms or suspected misuse.
Acceptable Use. You shall not use the Nimonik Online Store in any unlawful manner; attempt to gain unauthorized access to, interfere with, or disrupt the Nimonik Online Store or its underlying systems; introduce any malware or other harmful code; or use any robot, spider, scraper, or other automated means to access, harvest, index, or copy the Nimonik Online Store or its catalogue, except for standard search-engine indexing. You shall not resell, or provide commercial access to, the Nimonik Online Store. You shall not circumvent, disable, or interfere with any security, access control, or digital rights management (DRM) or other technical protection measure applied to the Nimonik Online Store or any Product.
Website Intellectual Property. The Nimonik Online Store, including its design, layout, text, graphics, logos, and trademarks is owned by Nimonik or its licensors and is protected by applicable laws. Accessing the Nimonik Online Store grants you no rights in it other than the limited right to access and use it to browse and purchase Products. Use of the Products themselves is governed by Part B.
Website Availability. The Nimonik Online Store is provided on an “as is” and “as available” basis. Nimonik does not warrant that it will be uninterrupted, error-free, or secure, and may modify, suspend, or discontinue all or part of it at any time without notice. The disclaimers and limitations of liability in Part A, Section 7 apply equally to your access to and use of the Nimonik Online Store.
This Part D applies to Parts A, B, and C and to all access to and use of the Nimonik Online Store and the Products.
Governing Law and Dispute Resolution. These Terms are governed exclusively by the laws of the State of California, United States, without reference to its conflict of laws principles and to the exclusion of the United Nations Convention on Contracts for the International Sale of Goods. The parties consent to the exclusive jurisdiction of the state and federal courts located in California, United States. In any action to enforce these Terms, the prevailing party shall be entitled to recover its reasonable attorneys’ fees and costs.
Changes to these Terms. Nimonik may amend or update these Terms at any time by posting the revised Terms in the Nimonik Online Store. The version of these Terms in effect at the time an order is placed governs that order, and the version in effect at the time the Nimonik Online Store is used governs that use. Continued use of the Nimonik Online Store or any Product following any change constitutes acceptance of the revised Terms.
Order of Precedence. Parts A, B, and C are to be read together as a single agreement. In the event of any inconsistency concerning the use of a Product, Part B prevails; in the event of any inconsistency concerning use of the Nimonik Online Store, Part C prevails.
Customer Terms Excluded. Any terms and conditions proposed by the Licensee, whether referenced in an order or contained in any other document, are expressly excluded and shall have no effect.
No Trademark Rights. Nothing in these Terms grants the Licensee any right to use Nimonik’s or the Owner’s trademarks, logos, or other brand identifiers. Any such use requires separate written authorization, and any unauthorized use constitutes a breach of these Terms.
Electronic Communications. By using the Nimonik Online Store or placing an order, the Licensee consents to receive communications from Nimonik electronically, including invoices, notices, and other records, and agrees that such electronic communications satisfy any legal requirement that a communication be in writing.
Force Majeure. Nimonik shall not be liable for any failure or delay in performance resulting from causes beyond its reasonable control, including acts of God, natural disasters, labor disputes, carrier delays, failures of telecommunications or internet services, governmental action, or other events of force majeure.
Assignment. The Licensee may not assign or transfer these Terms, or any rights or obligations under them, without Nimonik’s prior written consent. Nimonik may freely assign these Terms. These Terms are binding upon and inure to the benefit of the parties and their permitted successors and assigns.
Waiver. No failure or delay by Nimonik in exercising any right under these Terms shall operate as a waiver of that right, and no single or partial exercise of any right shall preclude any further exercise of that or any other right.
Severability. If any provision of these Terms is held to be invalid, illegal, or unenforceable, it shall be limited or reformed only to the minimum extent necessary to make it enforceable, and the remaining provisions shall remain in full force and effect.
Entire Agreement. These Terms (Parts A, B, C, and D), together with the applicable order confirmation, constitute the entire agreement between Nimonik and the Licensee with respect to the Nimonik Online Store and the Products, and supersede all prior or contemporaneous understandings or agreements, whether written or oral. Headings are for convenience only and do not affect interpretation.
Please read these terms of service ("terms", "terms of service") carefully before using Document-Center/Nimonik website (the "service") operated by Nimonik ("us", 'we", "our").
We will provide their services to you, which are subject to the conditions stated below in this document. Every time you visit this website, use its services or make a purchase, you accept the following conditions. This is why we urge you to read them carefully.
Before you continue using our website we advise you to read our Privacy Policy regarding our user data collection. It will help you better understand our practices.
Content published on this website (digital downloads, images, texts, graphics, logos) is the property of Nimonik and/or its respective licensors and protected by international copyright laws. The entire compilation of the content found on this website is the exclusive property of Nimonik and its respective licensors, with copyright authorship for this compilation by Nimonik and its respective licensors.
The entire communication with us is electronic. Every time you send us an email or visit our website, you are going to be communicating with us. You hereby consent to receive communications from us. If you subscribe to the news on our website, you are going to receive regular emails from us. We will continue to communicate with you by posting news and notices on our website and by sending you emails. You also agree that all notices, disclosures, agreements and other communications we provide to you electronically meet the legal requirements that such communications be in writing.
This privacy policy will explain how our organization uses the personal data we collect from you when you use our website.
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Our Company collects the following data:
Your data protection rights:
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