VIAIR 250C-IG Compressor

We found this compressor that by the looks of it meets requirement of FRC rule book for 2014 season.
I wanted to hear your guys input especially if I missed something in the rules.
Because it looks like far superior compressor comparing to VIAIR 90C while still under FRC’s 1.05 CFM limitation.

Yep it’s legal (the 12v version), we used it and loved it! It is heavyyyy so we can it off board.

Thanks Mk.32 for quick reply. It’s good to have a confirmation.
Before we found it, I started to work on a heat sink design for 90C cause it was getting very hot even with small fan. I probably better finish design, share it and may be someone would benefit from it.

It is a fantastic piece of hardware. Never even got too hot to touch. It’s hefty, but if you need the air, it’s worth it. We were asked by probably 10 teams about it and many seem very interested. If you can afford the weight costs, by all means get it. We won’t be using the others ever again unless we are too close on weight or don’t have many pneumatics. We were a little worried about current draw, but it’s no worse than the 90c. Be aware that Q&A said that it is required to use the stainless steel braid leader line and you need to design for that since it is heavy and cumbersome.

Thanks, good to know.
Q&A you are referring to, is it Q325?

Yes, that’s the one, bit of a bummer since it weighs so much and is hard to deal with

I compiled comparison table of compressors I found meet the FRC requirements. I hope it may help someone

Compressor comparison.pdf (240 KB)

Compressor comparison.pdf (240 KB)

And here is heat sink design I was working on.

I believe his is another FIRST approved compressor which I was told 254 used this year and with 17 pistons it probably got a good workout (someone may want to check me on both of those). It is only a little heavier than the KOP compressor too

we used this to good use.

Oh yes, thank you.
I saw that one but was too lazy to add it to the list. It seemed not much better, yet quite a bit more money.
On the other hand it still viable option and will add to the list.

Does anyone know how this compressor compares with the old KOP compressors as far as weight and fill rates?

Yes, see the comparison table I compiled

WildStang also used the new (Viair look alike) Thomas compressor. We liked it but it does not have a mounting flange or hardware. We considered that using any of the hardware on the compressor to mount it likely violated the “do not modify” rules so we made a custom bent aluminum tray for it. (Look for a change in the future.)
As pointed out, the Viair compressor comes with a stainless steel hose that is required by the manufacturer and so is required by the Q&A.

This compressor? We used it this year. Great for weight savings and cfm is alright, but it really, really likes to heat up. We thought we’d give it a try after 254 used it last year.

When we purchased our 215 Thomas compressor, it came with a large U-shaped bracket and a rubber mounting gasket. We replaced the bracket with large hose clamp. We placed the clamp around a frame member and tightened it enough to where a student couldn’t rotate it in the rubber gasket. It never moved after mounting.

Link to mounting hardware pic:

We had used the attached for comparisons earlier. (405 is the old Thomas KOP compressor, 415 was a similar model.)

Some comments:

  1. The notable difference between the Viair 250C-IG and the Thomas 215 is duty cycle - 10% for the Thomas, 100% for the Viair. The weight is unfortunate, but it’s a nice compressor.

  2. In using the 90C, we used one of the KOP muffin fans blowing down over the cylinder - it helped a lot.

  3. The 330C-IG on the chart is the bigger brother of the 250C-IG, but isn’t within the FIRST limit.

  4. When we asked the question, we were hoping that we would be allowed to use the braided hose (yes, it weighs more, but it’s the piping right after the compressor that gets the most thermal abuse). Required was a surprise, but the net result was the same. :slight_smile:



Mounting fins to the motor case may work, but most of the heat is being generated in the cylinder, and not in the motor (Viair, for instance, specifically mentions not mounting the compressor upside down, because they find that more heat transfers from the cylinder to the motor.)

What we found is that just having a fan blow on the cylinder head kept the compressor temperature reasonable.


Here is Updated Comparison Table. Thrown CFM graph for better visuals.
Also added table with just Viair 90C & Thomas 215ADC38/12. Sort of to compare compressors that very close in weight and size category.
Judging from the spec sheets, it seems to me that the only reason to chose 215 over 90C is for slightly better endurance and better initial CFM performance up to 20 PSI.
I am pleased that Viair 250C-IG is legal and I think it’s worth looking elsewhere on the bot to win those extra 4lbs that this compressor adds

Compressor comparison.pdf (277 KB)

Compressor comparison.pdf (277 KB)

We also had fan blowing at the cylinder head. However we also found that our compressor was so overworked that motor was very hot as well. May be not hot enough to cause 1st degree burns, but I wasn’t dumb enough to test that :).
One of the reason for extra working time probably due to a minor pressure loss that we were unable to locate. I soped the heck out of it and didn’t see any bubbles :frowning:

As I looked at the design I posted it occurred to me that it is perhaps an overkill. I will put more thought to it and if I can make it simpler while still effective.