I have no idea how much speed the AC robs. But this:
I've also noticed in some cases I have the issue of the nose wheel locking drastically to one side causing the plane to be uncoordinated without lots of rudder input until I touch down and then you can feel the nose snap back to straight when it touches the ground.
... is a telltale of the nose wheel issue.
Take a look at the AMM to better understand how the nose wheel fork is attached to the strut. There is a friction system that is adjusted by tightening a nut, using a mixture of black magic and luck. It will last whatever it lasts, but then you can do it again...
LTek1 wrote:For what it's worth, my 2003 is also a 130kt machine. No powerflow, though, which I suspect is most of the difference.
I have an older DA40 as well, a 2002, but it also happens to be quite lighter at 1691lbs empty weight. It doesn't have Powerflow either but it has the 2-blade aluminium prop and fine wire plugs. It cruises at 138-142 KTAS around 7-8k' at peak EGT on about 8.5gph. This is pretty close to the AFM numbers. The speed varies within that range mostly due to CG and gross weight. CHTs remain below 380 in this configuration since installing the Arizona baffle.
I finally had the cowling off and remembered to look at the baffles. It does looks like my baffles may have leaks. At least there are slight dimples on one of the baffles and on the underside of the cowling for all other baffles you see where it rubs the cowling but where these dimples are it's clean, no rubbing.
Regarding CHT, I've gotten much better with managing it and I can consistently get 135-137kts cruise while keeping the CHT below 380*. I think it was just a learning curve.
If I wanted to fix these waves in the baffles would I have them replaced? I think I read a thread about using some kind of filler to fill in the low spots.
The silicone baffles are the most likely culprit but also check the hard (grey composite fiberglass) baffles. They are somewhat brittle and a careless mechanic may have done damage. I would also find out why you have permanant indentations in your silicone baffles. I helped another DA40 owner replace the factory baffles with thicker gauge orange silicone baffle material. They work well and hold a tight fit.
beetlebug wrote:I finally had the cowling off and remembered to look at the baffles. It does looks like my baffles may have leaks.
Definitely.
But don't forget to check the gaps between the hard composite baffles & the engine case. That was the biggest source of leakage for me, especially near the spinner. Plugging the gaps with RTV is cheap and easy.
Sounds about the same as my 2002 DA40. No power flow, two blade hartzell metal prop. No speed gear but I do have the speed fairing on the nose gear leg. I think that fairing alone gave me a few knots.
Joey wrote:At 7 to 8k I am generally cruising 137-139, 2400 rpm and 9.3 gob. Lower altitude at 4500 I can see 142 at 2500 and 9.7. But pulling back to 2400 and 9.3 only takes a few knots away.
I have a 2008 model xls w power flow and a 2 bladed aluminum prop.
Look at the wear marks on the silicone in the areas you are talking about. Do they rub on the top cowl? Remember that the area blows up like a ballon. Those dimples may not be there with air pressure.
beetlebug wrote:I finally had the cowling off and remembered to look at the baffles. It does looks like my baffles may have leaks. At least there are slight dimples on one of the baffles and on the underside of the cowling for all other baffles you see where it rubs the cowling but where these dimples are it's clean, no rubbing.
Regarding CHT, I've gotten much better with managing it and I can consistently get 135-137kts cruise while keeping the CHT below 380*. I think it was just a learning curve.
If I wanted to fix these waves in the baffles would I have them replaced? I think I read a thread about using some kind of filler to fill in the low spots.
