On the Thomas 215 in comparison to the standard Viair 90C Air Compressor

Recently I’ve been looking into standardizing our electrical and pneumatic systems in preparation for the 2021 FRC season, and most notably have come across the Thomas 215 compressor as a possible alternative for our current compressor, the standard Andymark Viar 90C.

Looking to threads like:





…and a few others,

certain other members of our team have expressed interest in the possibility of testing and possibly using the Thomas as an alternative to the Viair during and possibly after the 2021 season.

However, certain mentors on our team have expressed worry at the possible illegality of the compressor, as well as its overall competitive benefits over our current Viair.

His concerns are quoted as follows:

  • the max pressure rating on that is 120PSI;

    the game manual says it needs to be rated to 125PSI

  • the viair compressors are mentioned by name in the game manual

    specifically that they have a 120PSI max working pressure but a 125PSI intermittent pressure

    the listed intermittent pressure rating on the thomas compressor is 120PSI

    which based of the wording of the blue box in R79 would make me believe it is illegal

  • that compressor is heavier than the compressor we use

    its 2.4lbs

    vs the 3lbs of the one you linked

    the one that you linked does have a higher flow rate so it might be worth the weight


Any thoughts?
Anything would be helpful.

IIRC, the Thomas is the old KOP compressor. Tank, heavy, not great CFM under load as I recall but very durable.

In 2018 we tested all the compressors (AM, Viair, and Thomas) in how many times we could actuate a cylinder over a match time in the test system. I think the Thomas compressor was a maybe 10% improvement over the others in that test.

But the main reason we went with it is because is can run continuously while the others are something like 15% duty cycle. We were refilling a 2.5 gal tank between matches which took about 6 minutes. So we could use the extra duty cycle, especially on short turn around times.

It is, of course, quite a bit heavier. But if you need lots of air it is better than the other two above I think.

I didn’t have the newer compressor to test, so that could be another option: NEW Compressor for 2020!

edit: I mean the older Thomas KoP compressor (THOMAS 1/10 HP Piston Air Compressor, 12VDC, 100/100 Max. PSI Cont./Int. - 5Z349|405ADC38/12 - Grainger). We didn’t have the 215, which like others mentioned is popularly used by a certain other team.

The Thomas 215 is different from the old KOP compressor – we’ve used it since 2014 after reading on Chief that 254 used it. It’s been pretty smooth sailing since we switched.

From our testing, it gets to 120 faster than the old Thomas compressor and can take a fair amount of abuse before it needs to be retired, but like other smaller compressors will heat up quicker. We haven’t benchmarked it vs. the Viair 90C.

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Hi Siddhesh,

While I don’t have any advice on this topic, there are some calculators that may be of use to you. @AriMB has a pneumatics refill calculator here. I have also implemented a very early alpha web version of a similar calculator here, with support for the VIAIR 90C, 98C, 100C, as well as the Thomas 215 and AM 1.1 Pump. You can view system pressure over time starting at 115 PSI and it will attempt to model the system pressure as cylinders are actuated, factoring in dynamic CFM rates as well as when the compressor turns on/off in the FRC ecosystem.

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Here is something interesting, but I’m not sure what discussion it was uploaded originally into: https://www.chiefdelphi.com/uploads/default/original/3X/3/1/312a205c85a54041193e0b321f6544895006fcde.pdf

696 has been using the Thomas 215 since at least 2016. It works well. It does still get plenty hot, but I’d say it’s not as worrisome as when the Viar gets super hot. We had one robot with a substantial leak, and the compressor ran basically continuously for quite some time. We’ve never had an issue with the Thomas 215 compressor, though I will say we typically haven’t used the same one year to year.