Small Gas 3D

[Abrams]

This has been very enlightening. I really like these little engineering exercises. It's a shame that my Edge 540 experiment didn't work out, but ultimately I think I would be looking for another air frame.

Enterprise, I'll be interested to see how your project works out. Cwojcik, thanks for turning me on to Enterprises thread. Snowdog, thanks for the link to the Vyper thread.

I'm starting with a DLE20. I like the characteristics of this engine. Since I am starting there, I think it only makes sense to pony up and buy the air frame made for that engine. I talked to the war department about getting the Volex 70. I think that's the way I'm going. No science project this time.

 

[SnowDog]

You will be glad you went this route!! The Velox and the dle-20 are the perfect match. Only question now is which color scheme,.

 

[Dr. Gonzo]

How do these small gas engines really run? I mean the 30cc and up seem to run really solid. It has always seems to me as size goes down they get more cantakerous. This is a very interesting subject to me.

 

[Abrams]

The 20 with the stock ignition doesn't tune very well. A friend of mine just bought a plane used with a DLE20. He rebuilt the carb and replaced the ignition with a 50cc ignition and it runs like a champ.

 

[Dr. Gonzo]

I see. Seems like they would address that issue on future versions. I have enjoyed hecking out these small gasser builds. The flight times sound great!

 

[Jkim]

I have the Velox with the DLE 20. Great combo! But I can tell you that before installing you will want to install a "Bowman Ring" and lap sand the reed block to insure the reeds are sealing properly. This will help a great deal with the starting and idling. I can now choke flip 1 time, take choke off and it usually starts on the 3rd flip. You also want to check the timing. It should be at 28 deg. from TDC. According to Frank Bowman most of the smaller engines such as the DLE 20 are off just a bit. Mine originally was at 40deg and had to be adjusted to fire at 28 deg. I couldn't be any happier with this combo.

 

[Abrams]

I see. Seems like they would address that issue on future versions. I have enjoyed hecking out these small gasser builds. The flight times sound great!

I mentioned this thread that I could not find earlier. There is a LOT of good information about the DLE20 and how to make it run right. It is well worth reading.

http://www.theprofilebrotherhood.com/forum/viewtopic.php?f=2&t=31620

HERE IS THE JIST OF IT DLE intended this as a beginners engine. I've only read the story second hand at best, but someone was very insistent that DLE do something to prevent stalling at low speed. By stall, I'm not even sure they meant engine stall, but possibly tip stall on landing. So when you come from high RPM and chop the throttle, the RPMs stick at about 2800 RPMs, then there seems to be a time delay and it drops about 1000 to a reasonable idle. Ramping up, there is a 1000 RPM jump. All of this is achieved with spark timing.

To counteract this, I've played with the timing on mine and moved my hall sensor all of the way to the left. It works better, but I am still not pleased. The real fix is to replace the ignition with a 50cc ignition. Then the engine acts more like the one in the Velox video.

 

[Abrams]

I'm about ready to pull the trigger on the Velox, but they have hardly any spare parts listed. I emailed 3DHS and asked them about it. They answered back, "More spare parts are on order for the 70" Velox".

That tells me nothing about the variety of parts they'll have, like a fuselage or a wing... Right now, you have to order another $439 kit ($409 on sale) if you need a fuse or a wing.

 

[rppoind]

Guys couple things about the DLE 20. The engine originally came with a RceXL ignition marked "#7".
This shipped only with the 20cc engine. This was used with a higher timing ie 35-40 btdc. Resetting to the standard 28 btdc will not improve things. Newer engines come with a standard ignition and is set at around 28 btdc. You can replace the old unit with any RceXl that will fit your CM-6 plug. They do not come in cc sizes, one size fits all. You will have to modify your pickup to allow it to go to 28 degrees. However...................

the original will slowly improve with running if you are patient. I leaned mine down every other tank or so for some time and it is now a pretty good engine. It is in a Slide profile. Hope this helps.
Richard

 

[Enterprise]

I flew my GT22 the other day for the first time in a while. I changed the throttle servo (long story involving dth7). The throttle only works in a very small band. I have the geometry as good as I can get it and still there is a very silly throttle curve in it. The motor is silly quiet (84 db) and produces decent power. Not real hard to tune or anything. It is heavier than the DLE though.

Waiting on some parts to come in for the 15cc project.

I flew my 10cc Sabre today and I realize it was only a partially successful project. It does indeed fly 3D, but the plane's higher wing loading leads to having to fly it fast and it does not have the excess thrust that most 3D pilots are used to. I think a 57" Extra 330SC would be a OK project for this combo. It will not be super powered, but it would be a better flyer and be closer to design weight.

I have a Mintor 22 laying around looking for a home. This caught my eye, but there are no reports on the quality of the model.

http://www.milehighrc.com/Sbach342_20CC_AP.html