DA85 on pipe! Results please.

[cmcleary]

Gentlemen, I am currently flying a QQ 101" yak with Da85 and MTW RE3 pipe and this combination is an absolute monster!! The prop I am using is a NX 26x10 and I can easily get 6800 rpm out of the engine. I only have about 1.5 gals of fuel through the engine and once it is broken in I will be switching to a mejzlik 27x10. I only tached the engine once when I first started it and before any adjustments were made. I suspect now the engine is slightly broken in it will spin over 7000 rpm. From my previous experiences mejzlik props are very efficient and I should only loss a couple of hundred rpm's. I will burn up that last 1/2 gal of gas this weekend and then I will switch props and also switch to synthetic oil in the gas and I hope the results will impressive. The DA85 does vibrate a lot and I just noticed small cracks in the spinner in the corner of the prop cut-outs. I don't have access to alum. welding equipment so I will try to add some reinforcement to that area with some thin alum. sheet and JB weld. We will see how it holds up.

[3D Joy]

	Quote: Originally Posted by BigBird
	JakeTab, Anything will be quiter than the Slimline Pitts. Greeves and a 26x12 Mezlik is very mellow sound and pulls like mad. The diffrence between a full pipe and a standard can type muffler is night and day. JD

What RPMs with the 26x12x2 Mejzlik?
I'm looking for this prop for my DA-100. I think Somenzini used one in one of his Pythons.

[sprice50]

	Quote: Originally Posted by Jaketab
	Gentlemen, My DA-85 is currently running with a Slimline Pitts. Noise at our field as become an issue. Can anyone tell me, which - if any, tuned pipe combination would reduce the noise as compaired to the Pitts style muffler. Thanks - Jaketab

If noise is an issue I would recommend a cannister and 27x10.

[sprice50]

	Quote: Originally Posted by cmcleary
	Gentlemen, I am currently flying a QQ 101" yak with Da85 and MTW RE3 pipe and this combination is an absolute monster!! The prop I am using is a NX 26x10 and I can easily get 6800 rpm out of the engine. I only have about 1.5 gals of fuel through the engine and once it is broken in I will be switching to a mejzlik 27x10. I only tached the engine once when I first started it and before any adjustments were made. I suspect now the engine is slightly broken in it will spin over 7000 rpm. From my previous experiences mejzlik props are very efficient and I should only loss a couple of hundred rpm's. I will burn up that last 1/2 gal of gas this weekend and then I will switch props and also switch to synthetic oil in the gas and I hope the results will impressive. The DA85 does vibrate a lot and I just noticed small cracks in the spinner in the corner of the prop cut-outs. I don't have access to alum. welding equipment so I will try to add some reinforcement to that area with some thin alum. sheet and JB weld. We will see how it holds up.

I really think that you should go to a 28x10 Mej. A 27x10 will be underpropped and likely spin close to the NX 26x10.

[3D Joy]

A mejzlik 27x10 and 28x10 turn within 50 to 100 rpm of each other. The 28x10 performs better, the 27x10 is quieter.

[emvin]

Hey guys I have the da85 on a greeve pipe. Airframe is the QQ101 Like CMcleary said the combonation is ausome!!!

Here's the thing my 85 keeps blowing up. to be more specific the head bolts keep snapping. This was a new engine running 32-1 lawnboy. The first time it happened there was about a gallon through it rpm @ 6800 on a Mej 26 / 10. It was sent back to DA and without question it was repaired. They replaced the head and piston. So I got it back and started over this time it ran about 2.5 gallons through and rpms were peaking at 6950+/-. I was starting to feel an increase in power and thought all was well. Performance was ausume having a great time. Then it happened again. I as lucky to save the plane. DA has now replaced the engine. When I asked them if I was doing something wrong they told me no and had no real answer as to why this keeps happening.

Now once again I am starting from break in. any feedback???

EMVIN

[cmcleary]

After reading emvin's post I realized I was not alone. This past Sunday during the fifth flight I heard a loud bang. I didn't know right away what happened but the engine quit 5-10 secs later. After the dead stick landing and examining the plane if found two of head bolts were broken. I have read other posts and realized this is a common problem with the DA-85. Sent the engine back to DA a few days ago. Does anyone know their usual turn around for engine repairs? Before the incident I was using a mejzlik 27x10th with mtw re3 tuned pipe. I used a nx 26x10 for break-in and then switched to a mejzlik 27x10. The 27x10 and 27x10th appear similar but there are slight differences. The 27x10th has a wider blade but thinner airfoil. In my application the 27x10th has been the best prop. It spools up quicker than the 27x10 and does not rip like the 26x10. Maybe I will try a 28x10 a little later but for now I will stick with the 27x10th.

[emvin]

CM They give attention based on how you shipped to them. If you overnight it they will look at it that day, send it ground and it may take a week after it arrives to get attention. as far as return shipping they will only pay for ground. DA has overnighted and second day aired for me on there tab before but its not there policy.

How many gallons did you have through before this happened to you? Knowing that this is a common problem with this engine does not give me a good feeling. I was hoping that I had a lemon and this new engine I recieved will be OK. Still hoping. The whole weight savings thing kinda goes out the window if the engine is not reliable.

I flew the new replacement 85 this week so far it seems OK I am being very easy on it flying around mostly at half throttle with no hovering or big up lines. The engine does seem alittle hot is that from break in? There is very good air flow. Do you think that its this engine on a pipe causing this issue?? Why cant they use stronger bolts?? I am trying to understand the technical side of this. .

EMVIN

[cmcleary]

Emvin, I had about 5 gallons through the engine before it happened. It was actually the 5th flight that day and everything was fine up until then. I fedex'd the engine the day after it happened and DA had it the next morning. There were other forums indicating that the DA-85 had issues with the base gasket but I have yet to have that problem. If this happens again I may have to upgrade to the DA-100. I know several people that have the 100 and don't have any problems.

[Sired by Fire]

just upgrade.

[emvin]

Yes if it happens again I may have to upgrade. Then I will need a new airframe as well as the QQ 101 is set up for the 85. It would be a shame.

[Flatlandman]

	Quote: Originally Posted by emvin
	Yes if it happens again I may have to upgrade. Then I will need a new airframe as well as the QQ 101 is set up for the 85. It would be a shame.

People have put 100s on this airframe so if you want to move to a 100 give it a try before you sell the airframe.

[sprice50]

	Quote: Originally Posted by emvin
	Yes if it happens again I may have to upgrade. Then I will need a new airframe as well as the QQ 101 is set up for the 85. It would be a shame.

I think the issue may be the motor being underpropped for the type of performance you are getting from the pipe. You said you were getting 6950 on a 26x10 Mej. Imagine what was happening in the air. There would be big loads on the engine at that RPM.

I suggest getting a 28x10mej. I haven't heard of this occuring on a larger prop with the pipe.

[airlyons]

Hey guys... is there a sheet for mounting. ( with the lines and points for where to mount on the engine box)

Also... can you order custom headers? If so... from who?

What are your thoughts on mounting a pipe under the belly? No room in my Edge :-(

Thanks,

Chris

[sprice50]

I wouldn't go for a pipe under the belly personally. I would just run the new DA100 on stock muffs (about the same for noise) and power.