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How to Spec an Aircraft Vibration Isolation Pad: What to Send H-O for a Quote
The fastest way to a useful isolation-pad quote is to describe the system, not just ask for a material. An isolation pad's behavior is set by the supported mass, the pad stiffness, and the footprint together, so a quote built without the mass and the disturbing frequency is a quote you will revise. Here is the short list of facts that move an isolation part from a vague request to a real, manufacturable scope, and what our engineering team does with each one.
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The nine facts to send, and what each one decides
An isolation pad is part of a system, so a useful quote starts with the system, not the material. The nine facts below are what our applications engineering team needs to recommend a grade and thickness and convert it accurately. The first three define the isolation problem; the rest set the environment, the documentation, and the manufacturing. Send what you have and we will flag what is still open.
- Supported mass per mount, and the number of mounts. The mass on each pad, together with the pad's stiffness, sets the mount's natural frequency, which decides whether it isolates. This is the single most important number for an isolator.
- Available footprint and thickness. The area and the travel the pad has to work in. An isolator needs room to deflect, so the thickness you can give it is as important as the area.
- Disturbing frequency range or source RPM. What you are isolating from: engine or gearbox orders, a fan, a rotating machine. The mount's natural frequency has to land well below this.
- The qualification spec the assembly must meet. MIL-STD-810, RTCA DO-160, or a program profile. We do not run the test, but knowing the target shapes the grade and the damping discussion.
- Temperature range and hot-zone adjacency. Continuous and peak temperature, and whether the mount sits near a gearbox, bleed-air run, or unconditioned bay, decide between urethane, silicone foam, and cork.
- Environment. Exposure to fuels, oils, hydraulic fluid, ozone, or humidity, which can rule a family in or out regardless of its mechanical fit.
- Fire and flammability requirement. Whether the part lives where the FAR 25.853 interior context applies, and any UL 94 class your program expects on the TDS.
- Attachment method. Pressure-sensitive adhesive, mechanical capture, or a bonded assembly, and any liner preference, since this affects the converted form.
- Geometry. A drawing or DXF is ideal; a dimensioned sketch starts a quote; an existing pad we can measure works too.
From Request to Converted Pad
| What you send | What it decides |
|---|---|
| Mass per mount + frequency | The target natural frequency and therefore the grade and thickness direction |
| Footprint and thickness | Whether the pad has room to deflect and isolate |
| Qualification spec | The damping discussion and grade margin (MIL-STD-810 / RTCA DO-160) |
| Temperature and environment | Urethane vs silicone foam vs cork; fluid compatibility |
| Fire requirement | Documented grades and UL 94 class on the TDS |
| Attachment and geometry | The converted form: adhesive, liner, die-cut or waterjet, kit |
Qualitative guidance only; the natural frequency depends on your specific mass, stiffness, and geometry. Confirm grades on their current technical data sheets.
What engineering does with the list
With the mass and disturbing frequency in hand, we point you toward a grade family and a thickness that should place the natural frequency below your disturbance: PORON microcellular urethane for a compact, low-compression-set mount that holds its tuning, silicone foam where temperature or fire drives the choice, or cork wonder pads for high-load equipment.
The environment and fire requirement confirm the family, the attachment sets the converted form, and the geometry sets the converting method. The output is a grade-and-thickness direction plus a converted-part quote; the isolation analysis stays with you.
What happens after you send it
We confirm the grade-and-thickness direction and the converting approach, quote the converted pad to your drawing, and flag any open questions, such as a missing mass figure or an undefined attachment. For common configurations on materials we keep on hand, samples typically ship in three to five business days; standard production runs about two weeks after drawing approval, with expedited service available.
Every order carries the maker's force-deflection and compression-set data for the grade and lot under our ISO 9001:2015 certified quality management system.
The mistakes this checklist prevents
The list heads off the failures that cost the most time. Without the supported mass, a pad can be quoted that lands in the amplification region and makes vibration worse. Without the available thickness, an isolator can be specified with no room to deflect. Without the temperature and environment, a grade can be chosen that softens in a hot bay or swells in fuel. And without the fire requirement, a mechanically ideal pad can be removed at documentation review. The nine facts up front replace several rounds of revision later.
Frequently asked questions
What is the single most important number for an isolation-pad quote?
The supported mass per mount. Together with the pad's stiffness it sets the mount's natural frequency, which decides whether the pad isolates or amplifies. Send it alongside the disturbing frequency you need to isolate and the footprint you have, and we can point at a grade and thickness; without it, any pad recommendation is a guess.
Do I need to send a full drawing, or is a sketch enough?
A drawing or DXF is ideal, but a dimensioned sketch starts a quote, and we can measure an existing pad to reverse-engineer it. What we need early is the mass per mount, the disturbing frequency, and the available footprint and thickness, since those define the isolation problem before geometry is finalized.
Can H-O tell me which grade will pass MIL-STD-810 or DO-160?
We can point you toward grades commonly used in assemblies that target those profiles and convert the part accurately, but H-O does not run qualification testing and makes no pass or fail claim against a test spec. Knowing the target profile helps shape the grade and damping discussion; the qualification result belongs to your program and its test house.
What documentation comes with the parts?
The maker's force-deflection and compression-set data for the exact grade supplied, plus lot-coded traceability under our ISO 9001:2015 certified quality management system, and any fire documentation for the grade where the part carries a flammability requirement. Tell us what your program expects so the package matches.
How fast can I get isolation-pad samples?
For common die-cut configurations on materials we keep on hand, samples typically ship in three to five business days. Standard production runs about two weeks after drawing approval, with expedited service available. Lead time depends on the grade, the thickness build-up, and whether the part is a simple pad or a laminated assembly.
Send the system, get an isolation-pad quote
Send the supported mass per mount, the disturbing frequency, the footprint and thickness, and the environment, and we will recommend a grade and thickness and quote converted pads to your drawing.
Samples typically ship in 3 to 5 business days for common die-cut configurations on materials we keep on hand; standard production runs about two weeks after drawing approval; expedited service is available. MOQ varies by material and part.
Family-owned in Winsted, Connecticut since 1971 · ISO 9001:2015 certified · OEMs worldwide send us a drawing — and get back their part.
Related reading
Request a quote for your aircraft vibration & shock isolation part
Send H-O your drawing or describe the part—engineering reviews every RFQ and converts samples on your geometry.
Last updated · Reviewed by H-O Products engineering (ISO 9001:2015 certified converter, Winsted, CT).
References
- ASTM D3574 (flexible cellular urethane, force-deflection and compression set); ASTM D1056 (flexible cellular rubber); ASTM D395 (compression set).
- MIL-STD-810 and RTCA DO-160 (environmental and vibration test methods); FAR 25.853 (interior flammability context); UL 94 (flammability classes). Cited by designation; H-O performs no qualification testing.
- Manufacturer technical data sheets: PORON 4701 / 4790 microcellular urethane, silicone foam, cork wonder pads, SAE pressed felt, neoprene and rebonded neoprene.
This article summarizes vibration-isolation and NVH material-selection principles using the families and method designations cited on the parent application page. Comparisons are qualitative; mechanical values are per each grade's current technical data sheet, and no test results are quoted.
Test standards such as MIL-STD-810 and RTCA DO-160 are named by designation for orientation only; H-O performs no qualification testing and makes no airworthiness determinations. All parts are custom manufactured to order; minimum production run quantities vary by material and part. H-O is a converter, not a raw-material producer.