I am about to receive my first gas engine, a G-62 with the full Ralph Ultra Light treatment and adjusted squish clearance. Should be awesome. However, this is by far the largest engine I have worked with and I have nothing remotely suitable as a test stand. What does everyone use for stands to run gassers like this? I would prefer something I can build myself, functional is much more important than pretty. Pics are always appreciated, websites, plans, etc.

Thanks,
Mark

Best stand in the world for a gas engine is to mount it on a plane.. tune it and fly it

That's what I do.

What if I don't have an airframe built yet? And it is hard to test different exhaust options on the plane...


Mark

Had to build one.

http://www.youtube.com/watch?v=ygLLE9wypoA

Bill Vail
www.RCScreenProtectors.com

Nice stuff, Bill.

I am thinking of going with wood for this one, but I like the construction of yours. Very robust and sturdy. And it is pretty easy to weld up a few pieces as you have.

Thanks,
Mark

Most companies will tell you not to run their engines on a stand because there is not enough air flow to cool the engine enough. Wait until the plane is ready and go fly. That's the beauty of gas. Dennis

That still doesn't solve my problem of exhaust system testing.

And I say BS to that, why don't the multitude of people who DO run them on a stand not burn them up? Do people really think there is any more airflow when the plane is moving? The propwash doesn't change significantly stationary or moving. Do people burn up engines hovering or performing other slow speed 3D maneuvers? No. What kills engines is lean runs, low rpm and big prop loads, especially on a new, tight engine. I plan to run light prop loads and a bit extra oil in the first few gallons and not to lug it down to destruction. I am sure it will be fine. Ah, there I feel better now....Those opposed to bench testing/running in an engine can tune out now and those with me can carry on with the helpful info.

Now back to the question of a stand. Anymore info, ideas, things to incorporate into the stand? Things to NOT incorporate?


Mark

I've always read that you wern't supposed to break a gas engine in on a test stand. Test stands were just for testing and sorting out problems. I understand about airflow but if that was the case, why wouldn't my weedeater burn up? Hummmm.....

Bingo. Ask Dick Hanson how many engines he has bench ran (more than I will ever own, I'm sure) and how many he burned up. And that is a lot of exhaust and pipe testing, where the possibility of screwing things up is much greater.


Mark

here are two types -that yellow one above is sure nice!
I designed the big one so all running could be done standing up and walking around it -
after a while, standing bent over to hold things gets really old . The table on the iron one is about kitchen counter height. It was really easy to make - all pieces are simply 2x2 iron - straight cuts with overlaps except for the mounting frame.
I hate complicated stuff- -so I try to do things I need, as easily as possible
Ed's stand is a work of art - designed to fit in a 323 Mazda-- really !
Mine fit in between the captain chairs and front seats of my last Chevy van. but real criteria included something which could be wheeled and parked in garage. the wheels only touch ,once the stand is tilted forward
I once did a magazine review for an engine which had a mid range (3000rpm) shake so severe , it made that stand skitter on the concrete ! It was a "conversion type engine that would only start n run with the head facing down- otherwise the plug never got wet -

What a beauty!!!

Dick,

I like the second one, very nice. What wood did you use? It looks like a hardwood of some sort. I was thinking of something similar, but not such nice materials. I figure good old spruce 2x4's and so on should do the job for me. I assume you just add weight as required to stop it from moving around? I like the counter height top, I am old enough to not appreciate being bent over tinkering on toys anymore.


Thanks,
Mark

Ed made the wood one - from furniture grade stuff -I was surprised that the top wasn't matched Brazilian rosewood.
I would have used framing lumber ---at the prices for that stuff now -it is all I can afford . I used to pay 80 cents for an 8 footer. My first brand new home in 1967 - $22,000 --had all hardwood or shag carpet option ---same price - really -- and the underlayment was diagonal boards - squeaked pretty badly -I was always adding nails to fix squeaks.
Now -the new homes here have stucco exterior (yer choice of color) - and a starter home is $300,000.

Here is mine. Simple and works with anything I have converted including twins. Tested many engines with it. Here it is attached to the grill with a big clamp. Yes it is safe and doesn't move the grill as it has breaks. Usually I screw it to a table top.

Dick,

I'm with you, this thing has to be functional, not pretty. All I want is for it to be structurally sound and convenient to work on and with.


Mark

Tim,

Now that's something I can work with. I was thinking of a piece that I clamped to my Workmate portable bench, maybe not so far off after all...

Thanks,
Mark

I've built a few and seen a hundred over the years.

Here is a list of bullets in no particular order:

- Make it to a height you would like to stand and crank a finicky engine. Your engine is on a stand for a reason and may require some tinkering. It's nice if you're not flipping at eye level or kneeling to curb-height.

- Make it's as universal as possible. While today you are thinking G62, next week your club may start a killer class of 1/2A pylon racing you'd love to join.

- Make it stable. I don't mean stable like when things are going well. I mean stable when things go wrong. You will thank me the first time that Jett .90 throws a prop blade at 16,000rpm and the SOB starts shaking (shaking is an understatement).

- With big engines, weight is your friend... but make that weight removable. You won't use your stand if it takes 3 men and a boy to move it out of the shop into the yard for some testing.

- Make a provisions for a shelf behind the motor. Again your engine is on "the bench" probably because you want to work on it. That usually means a few tool and a good sized gas tank.

- Fuel proof it well. Making my first test stand in high school wood-shop proved to be the last test stand I'd make for 30 years. The yellow metal stand was the first new stand since 1978. Regular old polyurethane works well.

- You will need to make provisions for a big tank. Preferable 32oz. You would also like the tank height to be adjustable. Setting up your engine perfectly and setting the needles for your next big test flight means nothing if the tank is a foot to low.

- My first test stand was made of 3/4" marine grade ply and something of a box. In fact, was more like a speaker box. It worked well for years but it was loud. An open structure will serve you better.

- If you plan to do any testing over time, you will probably want to make provisions for a goo collector.

This is just a blast of the first few things that came to mind. I'm sure there are more. I feel like I'm giving up 30 years of test stand design in one post.... Oh well....

Bill Vail

I run 210cc engines on mine with full pipes --so the large size was mandatory--

Hi Tim220
what is that fine looking engine - your own coversion? Details
sid

Here's some pics of one I saw somewhere on the web. I saved the pics, because I would like to build one similar someday. I really like the changeable motor plate. Just build an adapter for each different motor.

Thanks, Bill. Sound advice from experience there. You are giving up 30 years of design knowledge, but it's helping those of us that haven't got the 30years in yet... Much appreciated.

Mark

Sid it is a conversion. Started life as an Echo CS-610 twin cylinder chainsaw. It is 61cc. Runs well. Only issue to deal with is the carb being on top so a round cowl plane would be ideal. Also thought about just turning it over and making a different exhaust. Could come right out the side or route tubes to the bottom. Too many other projects now so that will wait. Unless someone wanted to buy it of course. Here is a picture of another one I have to show you the before to go with the after. Lots of cutting and milling but it is worth it. Holes to plug for the bar oiler etc.
Tim

Tim,

Since we are a ways off topic here, what does your conversion swing for a prop @ what rpm? Nice clean looking job, very well done.


Mark

Mark the prop I used was a 22/8 and turned a little over 7000 RPM as I recall. BME did these with a different case and D&B Engines still makes them. They claim it will turn a 24 inch prop. Maybe but this was what I had here so I used it. Runs real well and the mufflers I got from BME sound very cool.

I should have mentioned this sooner, but I didn't build or design the yellow stand. A good friend, Chuck Harris, looked at the stand I had been using for years, drew up some plans for an improved one and built the stand I posted pictures of. He built two. One for him. One for me.

Chuck and I have discussed making these stands commercially. The topic of an engine test stand comes up often and it looks like there is a need for one. The good folks at PSP make a fine engine test mount and they do make a post to put the mount on but I think many modelers are looking for a movable stand.

Bill Vail