Author Topic: Old Force let me down. (Read 6674 times)

Paul Taylor · « **on:** April 22, 2014, 09:09:41 PM »

Last season my Force was running great with the LA 46.
First 4 flights this spring

the engine would go lean after take off. Put on a new clunk tank- same thing. Swapped engines same thing. Pressure- no pressure. Last two tries the plane never left the ground. I tried to get a needle setting of 9400 rpm and would run away. Tried a different prop too.
Sorry to say I gave up.
The conversion to electric has started.

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Steve Helmick · « **Reply #1 on:** April 22, 2014, 10:04:07 PM »

Wow, I'd never admit that I couldn't make a .46LA run pretty darned good. There really isn't any precedence for that, other than loose/leaky backplate or maybe a stuck wristpin, bad fuel, leaky hoses, or bad glowplug.

Steve

Dennis Moritz · « **Reply #2 on:** April 23, 2014, 03:04:59 AM »

Softened profile nose? Is that an ARF Force that was stripped and painted? On mine I wound up bolting an aluminum plate on the backside of the nose, side opposite the engine, engine bolts through the plate. If I tightened up the bolts every other flight, engine behaved. Otherwise. Looks great. Was it a scratch build?

Paul Taylor · « **Reply #3 on:** April 23, 2014, 06:13:58 AM »

Steve. It's not the engine or me. Read the post again. Two different engines - two different tanks. This is not an ARF.

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Brad LaPointe · « **Reply #4 on:** April 23, 2014, 06:17:11 AM »

Crap fuel ?

Paul Taylor · « **Reply #5 on:** April 23, 2014, 06:43:51 AM »

Maybe the title show have been " Force let me down". 😜

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Dennis Moritz · « **Reply #6 on:** April 23, 2014, 07:54:56 AM »

Did you use the same muffler? Possible loose pressure nipple or accumulation of exhaust crap.

Paul Taylor · « **Reply #7 on:** April 23, 2014, 08:32:20 AM »

The fuel is not the problem.
As I think about this a little more I think it's a vibration problem. Something I did not have last year. I wonder if sitting in my garage over the cold winter if something changed with the airframe. I felt a lot vibration in the fuse. It was like when setting the needle it would get to 9300 rpm then jump to 11000. It's hitting the right vibration frequency. Or in my case it was the wrong frequency. 😩

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Dennis Moritz · « **Reply #8 on:** April 23, 2014, 08:43:29 AM »

Bad vibes always need to be considered especially with a profile. Yes. I've had the airframes loosen up and change frequency. Aluminum pads under engine mounts, aluminum plate on back side of profile, as I described earlier. Steel engine pads. Cinching bolts tight with pads. Dan Banjok built a sweet looking Cosmic wind for Foxberg. Perty bird. Bad vibes. He wound up with steel pads under engine mount. There is also the inverse tetra tank, never described in print (too complicated!) that allowed Mike and Dan to fly formation with soft nosed ARFs. If you make it to Brodak talk to Dan.

ray copeland · « **Reply #9 on:** April 23, 2014, 08:56:09 AM »

Paul, my profile Chipmunk was having the same issues. I added an extra tie strap around the clunk tank , pulled it very tight and it settled right back down and runs great now. Keep plugging I think you can get it figured out.

Dennis Moritz · « **Reply #10 on:** April 23, 2014, 09:08:00 AM »

Inverse Tettra.

Paul Taylor · « **Reply #11 on:** April 23, 2014, 10:25:46 AM »

No going back.

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Zuriel Armstrong · « **Reply #12 on:** April 23, 2014, 11:02:51 AM »

Good work Paul. You will like it better now and I'll confirm that for you after I fly it

Michael Massey · « **Reply #13 on:** April 23, 2014, 11:05:00 AM »

Had the same thing happen to me on an "experimental" Pathfinder that I had. Different engines, tanks, fuel etc. etc. I added additional 1/16" stiffeners to the nose and that fixed the problem.

This goes back a couple of years but I had tried a thinner fuse with full length 1/32 plywood lamination's on each side. That was in the days when I crashed fairly frequently and was trying to make a stronger fuse. Believe it or not, the answer was much more simple than that...quit crashing.

bob whitney · « **Reply #14 on:** April 23, 2014, 01:55:29 PM »

did u change props

Paul Taylor · « **Reply #15 on:** April 23, 2014, 02:19:56 PM »

Yup

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Vincent Judd · « **Reply #16 on:** April 23, 2014, 03:06:31 PM »

Yeah, I'll estimate that on about the fourth lap of your first test flight, you'll be trying to figure out how quickly you can post all of your IC engines on E bay. Good luck with the conversion.

Paul Taylor · « **Reply #17 on:** April 23, 2014, 03:52:48 PM »

I still have a few Planes with LA 46 engines. I still like the smell of nitro early on the morning. 😄

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Jason Greer · « **Reply #18 on:** April 23, 2014, 07:50:00 PM »

Good luck with the conversion Paul. Hope it works great for you.

Dennis Adamisin · « **Reply #19 on:** April 23, 2014, 09:55:02 PM »

Wow, that is quick & DECISIVE action. I think you will be happy with the change...

Steve Helmick · « **Reply #20 on:** April 23, 2014, 11:35:04 PM »

Quote from: Paul Taylor on April 23, 2014, 06:13:58 AM

Steve. It's not the engine or me. Read the post again. Two different engines - two different tanks. This is not an ARF.

Embedding the picture in the text didn't help make the post very readable, added to the fact that the picture is too wide, causing the text to be wider than normal. To read the text, I had to scroll back and forth. Assume it would be the same for everybody.

Anyway, I recall Andrew Tinsley posting about his buddy in England with some puzzling problems after a Winter's storage. After much conjecture, a clogged muffler was the cause. So, did you use the same muffler on the two engines?

If you want to build an electric model, I think you're way better off doing that, instead of converting one, most especially a profile. But I hope it works well for you.

Steve

Paul Taylor · « **Reply #21 on:** April 24, 2014, 07:55:57 AM »

Thanks Dennis hope to see you in June.

Steve- sorry you have issues.
You might want to take it up with Robert or the people that developed the app. I have no control over how it embeds the picture.
As for the muffler it is a tongue type. No blockage.
I did talk with Bob Hunt before I got started. He said he had a few electric planes.

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Zuriel Armstrong · « **Reply #22 on:** April 24, 2014, 10:01:41 AM »

Paul

john e. holliday · « **Reply #23 on:** April 24, 2014, 10:09:09 AM »

Well I hope you are good with the electric. Would be interesting to really find out about the LA's thought. Have you tried them on other planes or just this one.

Paul Taylor · « **Reply #24 on:** April 24, 2014, 11:41:37 AM »

Hey Doc
I changed the title to old Force let me down. I'm not all that good with Electrics. Im more comfortable with IC. But I'm willing to learn and the guys in the electric section have been very helpful.

Here is the list again.

1. LA 46 - clunk tank, tongue muffler no pressure. Would not needle at 9300-9400 rpm. Would lean out.
2. Brand new Sullivan clunk tank. All new fuel lines. Same problem.
3. Swapped engine with ANOTHER LA 46 that I let a friend use last year. Put the original tank back on and added pressure. Same exact problem.
4. Removed muffler pressure. Same exact problem.
5. Took the TT 11x4 off and replaced with a APC 11x4. Same exact problem.

I would turn the needle out to a real wet two 8200 rpm. As i turned it in to 9300 it was like it found a spot and the engine raced up tp 11000 rpm.

My last comments on this.
IT WAS NOT THE ENGINEs! Nor do I think it was either fuel tank or the props. The nose of the plane did vibrate a lot more then I remember from last season. So I really think it was a harmonic vibration issue.
Something that will not effect the new power plant.

Tim Wescott · « **Reply #25 on:** April 24, 2014, 11:58:08 AM »

Quote from: Paul Taylor on April 24, 2014, 11:41:37 AM

IT WAS NOT THE ENGINEs! Nor do I think it was either fuel tank or the props.

But maybe the fuel? If last year's fuel had some anti-foaming agent in it, and this spring's fuel didn't? (I know -- you used the same @#$% fuel. But I'm trying!)

Paul Taylor · « **Reply #26 on:** April 24, 2014, 03:25:16 PM »

Nope. I got 2 gallons of new fuel a few weeks ago.
5/22 Lou's Brew the brew that's true. 😊

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