DA 100 Sags Inverted...any Ideas?

[Neil4]

Hey Guys,

I have a 35% Dalton Extra 260 with DA 100 and as you can see from the title of the thread it sags amd looses RPM when flipped inverted. I have no idea why it does this as I have never had a plane do this before. The only thing that I could possibly think of that could have anything to do with this problem is the fact that the tank is mounted higher than the engine. But even still, I fly a friends 35% Hanger 9 260 and he also has a DA 100 with the tank mounted higher than the engine, and he has none of these problems. Any advice would be appreciated.

Thanks,

Neil

[Andy Thomas]

Call DA on Mon. In the mean time try pulling your needles and check for gunk, then go back to factory settings.

[xtreem3d]

could fuel be puddling on the reeds causing a rich condition while inverted..

..air disturbance over the carb diaphram causing motor to go rich while inverted

[Vic3D]

Tank location has nothing to do with it. Carb pulls the fuel it needs. Check your low end needle settings. You could be a little rich, but I am betting that you have an airflow issue and you need a carb plate. Call DA to make sure.

[rcairflr]

Could be as simple as your needles set too rich. Try leaning needles a liittle bit at a time and see if your condition improves. Just because the engine sounds good on the ground does not mean that it will be good in the air.

[DKnippen]

Hows the plumbing in the tank itself? New or old? I've seen a few that as soon as they go inverted they run bad or quit because the fuel line in the tank is stiff and bent to the bottom of the tank.

[42Percent]

	Quote: Originally Posted by Neil4
	Hey Guys, I have a 35% Dalton Extra 260 with DA 100 and as you can see from the title of the thread it sags amd looses RPM when flipped inverted. I have no idea why it does this as I have never had a plane do this before. The only thing that I could possibly think of that could have anything to do with this problem is the fact that the tank is mounted higher than the engine. But even still, I fly a friends 35% Hanger 9 260 and he also has a DA 100 with the tank mounted higher than the engine, and he has none of these problems. Any advice would be appreciated. Thanks, Neil

Simple thing maybe over looked is if there is no drip loop on the over flow line over top of tank.
Have friends that didn't use the loop and it causes issues just like what you are talking about.

[camss69]

If it's the stock tank I would check it's integrity, mine failed.

I think you may also want to check that you have a big enough air exit hole. Your problem could be pressure building in the cowl causing the carb to go rich. You can try making the exit hole bigger and/or adding a baffle in the front to only let air in directed directly at the cylinders.

A carb plate will probably not fix the issue (it did not fix mine with the same setup), it is only meant to block a direct blast of air on the carb it will not help a pressurized cowl.

Just another thing to check...

[BOSSIER_ROB]

	Quote: Originally Posted by 42Percent
	Simple thing maybe over looked is if there is no drip loop on the over flow line over top of tank. Have friends that didn't use the loop and it causes issues just like what you are talking about.

The overflow has no bearing on how the engine runs. The loop is to keep from losing fuel when in a nose down attitude. Tank location doesn't matter on the gassers as they pump fuel into the carb. Check to see if your clunk line has hardened some. If it's become a little stiff, it might not be flopping to the fuel when you roll over. As several folks stated, could be a touch rich and having excess fuel puddling on the reeds.

[claselva31]

Hey guys I had a very similar problem on my DA100. Spoke to Keith at DA and thru discussing it we thought a diaphragm cover would help. I ordered one from Troy Built Models. Bill got it right out to me arrived Friday and installed it. Very simple to install. I've got some pics to show how it went. There are two thing I warn about when installing on a DA100:
1- when you go to reinstall the diaphragm cover remove the rubber diaphragm because it has a key on the plunger that has to fit into the fork on the float lever.It just slips into the fork but if you just mount the cover plate you in essence hold the float open.
2- Make sure you hang the bigger part of the carbon fiber plate down in front of the mouth of the carb. Two reasons one is it will hit the intake if you don't but better yet reason two is it will act like an air dam in front of the throat of the carb stopping any air from rushing past and pulling the air out of the carb throat thus ruining the venturi effect.
My engine was blurb ling terribly and you need to be careful; not to lean for that condition. If the engine runs strong on the ground and burbles in the air it's more than likely an airflow problem.This fixed both of my problems on my Performance Aircraft Ultimate 37%. I believe it will help you also. Chris