Forward facing clunk
 

Folks,
Any experience with a forward facing clunk tank setup. What I mean is that the fuel stopper is at the rear of tank instead of the front. Would this allow the clunk to become exposed and suck air more often than a rear facing clunk? NO LEAKS IN THE UAT. The air IS coming from the main tank. I can run up the turbine for 5 minutes and not one bit of air gets into the UAT. I go fly for 3 minutes and the UAT is 1/3 full of air.

Any thoughts or comments? Any one with similar setup that can adivse. NO guesses please....To much invested for that.

Dave

RE: Forward facing clunk
 

Forward facing clunk WILL pick up air in flight............. sitting still on the ground maybe not.

While test running on the ground for that three minute run, did you pick up the aircraft and point the nose to the sky? Try it I'll bet you get air in your UAT.;)

RE: Forward facing clunk
 

Good point. I thought the dymanics of flight would be different from just pointing the nose up. I experienced a flameout on takeoff just after I jit the retract switch. I had about 1/4 tank left. I wonder if the accel of take off and the all too short climb out got the fuel to rush towards the rear of the tank and thus exposing the forward located clunk?

Dave

RE: Forward facing clunk
 

yep!!!!!!!!!:D;):D Turn that tank around.

RE: Forward facing clunk
 

Forward facing clunk will not work. Have tried it on two planes, have had two crashes. Have tried various variations on the theme...it won't work.
Change your tank around. Period.

RE: Forward facing clunk
 

It WILL work...but you have to fly backwards.;)

RE: Forward facing clunk
 

ROFLMAO!!!!!!!!!!!:D:D:D

RE: Forward facing clunk
 

I'm a believer too! I've had 2 flameouts. The first I chalked up to an air leak. Redid the entire fuel system, pressure checked it. I'm turning it around.

Thanks!

Dave

RE: Forward facing clunk
 

Dave,

HAve you asked all the other R54 flyers if they are having any problems with the "Reversed" fuel tank. I have only had a few flights
but have have had no trouble with flameouts. I ran the engine on the ground many times and held the nose up for a few seconds. I did a vertical climb on sunday and it was about half way into the flight so the tank was not full.

Am I correct in assuming that you are the only one with a Kevlar tank? I am just about to install my Keval tank. I am a bit nervous about that now.

What sort of tube are you using inside the tank?. I use BVM tube. It is very soft.



Regards

RE: Forward facing clunk
 

Tommy,
It WILL run perfectly sitting on the ground, meaning no air in the UAT. I take off and fly for a few minutes and low and behold, air in the UAT. Yes, I'm using a Jet Tech tank...I don't see why this would be a problem. The first flameout I ran the UAT dry at 6 minutes.

The last flame out occurred with @ 1/4 tank on take off. "Just shooting touch and goes". I'm certain the fuel was pulled to the rear of the tank during take off acceleration and climbout. You guessed it..Just as I retracted the gear..she quit. Off field landing, she'll fly again with a conventional tank layout as soon as I reinstall the boattail and fix the crumpled leading edge. I'll post pictures. Its easy enough.

Bruce makes a beautiful airplane. It's the fuel system that is not working for ME.

Dave Rigotti
Maybe its my style of flying. I fly it fairly aggressive with many loops, rolls and combo manuvers. I HATE snap rolls so I don't do 'em.

RE: Forward facing clunk
 

Dave,

I have never checked to see if the UAT was full at the end of my flights so far. I will next time I fly. I do recall when I was defueling that I could see fuel in the top of the UAT.
I just wonder why nobody else has reported the problem. I thought when I was building the thing that the tank was in the wrong way. I had to get the plans out and check. Perhaps bruce can share his experiences. He has had more flights than all of us put together.

Regards

RE: Forward facing clunk
 

Once ago I was giving some thoughts to the same issue, and the bellow idea came to my mind, of course, depending of your tank geometry.
Is not perfect, but it is better that just simple installing the tank facing aft.-
Good luck.,-

RE: Forward facing clunk
 

Thanks....I worry about the clunk getting hung up on the feed tube.

Dave Rigotti

RE: Forward facing clunk
 

Dave,
of course there's that possibiliy[:-], but depending on the lenght (shorter better) of the tygon tube and considering its rigidness....there is a good chance it could work.-
For sure if you roll the plane the tube will hang as we dosen't want to....[&o]
Grap a piece a brass tube and a tygon tube w/clonk in your hand and make a test....anyway with your needs, this way could be better than nothing....

OR.....:

RE: Forward facing clunk
 

The forward facing clunk probably works fine with the BVM tubing that Tommy is using. It is the most flexible tubing I have ever seen.

Fuel line (36") BVM #2804 $5.00