DA-70

[ryan_m]

I bought the cover from ExtremeFlight. It is for their Yak 54, I cut the heck out of it. And painted it. Paint didn't stick well, but as long as fuel stays off of it it seems to stay fairly well.
In the pic of your Yak you can get an idea why I cut those ovals to the side... the 3dhs cowl curves around a whole bunch more. Covers most of the cylinders up. Especially the head where the hottest temps are. I wish they didn't wrap it around quite as much as they did, if it went about 1/2" less all around I think it would cool much much better. But it isn't, and so the ovals seem to get the job done too.

Oh, and the baffling material I used is EVA foam from hobby lobby. Cheap, flexible, and doesn't burn. Works well for baffling.
http://www.hobbylobby.com/Crafts-&-...-Foam/Black-5mm-Thick-EVA-Foam-Sheet/p/111098

 

[emtp275]

@mulehead1969 and I bought a couple DA 70's last month finally got around to busting mules off after a morning of flying with @ChickenBalls, this is going to be a sick motor! Fired in 5 flips with choke on and was running in 3 more. I had planes to put mine on a rebuilt 89 slick but now I'm almost afraid I'll end up ripping the airframe apart so it may find its way into my 91 yak. All I can say is it is amazing and has less than an hr on it now I can't wait to see what happens after another gallon or so.

 

[ChickenBalls]

@mulehead1969 and I bought a couple DA 70's last month finally got around to busting mules off after a morning of flying with @ChickenBalls, this is going to be a sick motor! Fired in 5 flips with choke on and was running in 3 more. I had planes to put mine on a rebuilt 89 slick but now I'm almost afraid I'll end up ripping the airframe apart so it may find its way into my 91 yak. All I can say is it is amazing and has less than an hr on it now I can't wait to see what happens after another gallon or so.

This is the second start up of @mulehead1969 's DA70

 

[Phil.Griffin]

The little 70's are wonderful engines. I have hundreds of flights on mine.

 

[49dimes]

I can officially comment and say "Yes they are" Phil. Most happy to be in the DA 70 family of engines.

 

[emtp275]

Started on the next 70 install need a little advise, This is a 3DHS 89 Slick V1 that I rebuilt, the openings on the v2 cowl that I am using are smaller than the V1, I am slightly worried about cooling issues, I marked this on off to cut it to match the old cowl, It has to be split and painted so not worried with how the cuts will look, This will be baffled and my question is dose any one think I need to open the front or does this look like it will allow proper air flow?

 

[Ohio AV8TOR]

Don't forget to think 2.5 times more about how the air gets out.

 

[49dimes]

I would open it up only about half of what you outlined with tape. Make some decent side baffles as well as lower to get the air directed on to the cylinder. Not starting a war here but I personally have found that an exit opening about equal to the inlet area works fine as long as a "drag lip" is installed in front of the exit opening. Since you are doing work to the cowl might want to try a couple of those pre fab louvers that vvrc sells. I am going to put a couple on the top of my 330sc.
Success to you and your rebuilt Slick .

 

[emtp275]

I did not end up opening the cowl and it seems to be doing good with baffles and plenty of exit space, but that being said in have also been flying in 40deg temps.