chevy43

Today I got my .061 Wasp. I mounted it up in the test stand and put a RJL head on it. The RJL head says to use a copper gasket so I went out to my box of cox stuff I saved since '74 and got a head gasket. Well that was a mistake because there already was a aluminum head gasket down in there that I couldn't see. That caused a lot of wasted time till I figured it out.
Skaliwag was over here helping me too. He has a realy good feel for diesel tuning - Thanks buddy.

I filled my tank with my " Baker Black Brew Bunker oil #2. I took alot of work to get it to run. I really never did run very well on my mix so I did a half Davis half BBB mix. It ran OK but the idle just isn't good. So I ran it on straight Davis it still doesn't idle well. I tried both a 6x3 and a 7x4. Got 10,800 on the 7x4 but the 6x3 only gave me around 12,500.

My paw runs pretty well on my "BBB" fuel and turns the 7x4 about the same rpm.

I put the glow head back on it and it runs great and idles really well. It turns a 7x3 at 12,600 with a peak of over 13K and idles well at about 3K. It starts with a flick of the fineger. This is a great running glow engine but not a very good diesel convesion - at least for me. I was running it on only 15% nitro

The PAW running my mix and the AP Wasp running glo seem about the same power.

The AP Wasp is almost an ounce less weight.

For a 1/2 A The Wasp seems really nice and idle and throttle response is great - as a diesel not so good for me.

NorfolkSouthern

That's good information to know, and it's nice to have a 1/2A engine available, since there aren't any others known on the market besides Thunder Tiger. I may consider one of these for a Herr Star Cruiser or Little Somethin' Extra.

NorfolkSouthern

Wayne C

Truthfully, there are a lot of 1/2a engines available. OK Cub, Brodak, CS, and several others.

ptulmer

My Feedback: (5)

Ok, there's just no good 1/2a engines being mass produced...

http://carlsonengineimports.net/

Cipolla, MPJet, AM and a few others going down to .09's.

chevy43

I do have one compliant so far about this Wasp. The needle valve body fit is loose in the carb so when you touch the needle it wobblels and affects the mixture. You have to be really carefull and let the engine stabalize after each adjustment. If it had been a good fit it would've been much nicer.

Of course the carb screws came loose too but that is pretty normal. They need Lock Tight.

rainedave

My Feedback: (1)

chevy43, I'm sure you balance your props, but I'll say anyway that reducing as much vibration as possible it crucial with these Wasps. And make sure there's no play in your throttle to servo hookup. The other side of that coin is that the two Wasps I've adjusted have a pretty wide needle range; they are not one or two clicks critical.

chevy43

How much more power will I see by running 1/2a fuel instead of the 15% nitro that I'm running now aproximately? What is typical 1/2a fuel? 25%?

This engine will peak at 13,800 with a 7x3 on 15% nitro then it starts to slow down. Does that mean I need to add another head gasket?

chevy43

Ok I put another head gasket in there and it peaks at 13,400 and sags back to 12,400 which is worse than without the 2cnd head gasket. Also I think I don't have as good an idle so I'm pulling one gasket back out.


Later today Skaliwag is going to give me some 25% to try....

ptulmer

My Feedback: (5)

Chevy, make sure a large portion of the oil is castor. And yes, the higher nitro content should make it easier to run and throttle. I run 35% in all my 1/2a engines. The nitro and castor is more important the smaller the engine. Don't get me wrong, you can run with lower nitro. It just gets easier for me with the higher %.

ptulmer

My Feedback: (5)

Ooh! I just saw what prop you are using. Back down to a 6x3 max! Go as low as a 5x3 for max performance. It's sagging because you've got too much load.

chevy43

I ran a 6x3 on it but it didn't seem to turn all that much faster and the idle wasn't as good and it was really loud!!! They do show a 7x3 as the max sized prop to run. Also I'm going to be running about 1/2 - 3/4 throttle and only bursts of full throttle.

I'll try the 6x3 Cox prop again and see if I can get it to turn up faster.

chevy43

Well it peaks at 15,300 and sags back to 14,800 on the 6x3 Cox prop which is definetly more power but probably will run out of fuel faster and makes more noise. Desisons Desisons.....

Andrew

Stick with PT's advice -- 6x3 is all you need on this engine.

How much castor is in the fuel you're using? Too much load can cause overheating (and sagging as noted above) -- castor has two advantages over synthetic. It has a higher flash point and a higher film strength. The higher flash point keeps it from burning off when the engine gets hot, consequently, it carries a lot of heat out the exhaust.

Also, slip a piece of fuel tubing over the needle to snug it up and seal air leaks.

chevy43

I'm using power master 15% nitro 18% oil and it just says synthetic/ Castor blend. Probably low on castor to save themselves money. The engine doesn't seem to get all that hot on the 7x3 but I should look at it with the laser temp gun and see what it says.

I don't have any special 1/2a fuel right now and I'd love to not have to buy special fuel either. I don't need max performance - just a good running engine that idles nicely is all I need. This engine will not be running full throttle like the poor Cox's had to do all the time.

ptulmer

My Feedback: (5)

You can add castor to the fuel. I bring mine up to 22%, but you can go on up a little more if you need more cooling. Here's another thought, is the crank binding as it heats and swells? That's exactly what Flyswatter's AP .09 was doing and the crankcase would heat up like the fires of hell and turn a 6x3 up to about 15k.

flyinrog

My Feedback: (1)

So you've had this engine 1 day and your checking for peak performance?!!! Listen to PT first of all(6X3)..second do a search, I believe the last post on this engine showed that it needed like 20 tanks to break it in, not 3...and get a quart of %35 nitro..you can get benol racing castor for $5/quart at Tower, add it to the bottle to fill up the neck...put it on a plane and fly it rich for a while..I've seen 2 of these engines "come on" during flight and really pick up the right sound/pitch......Rog

rainedave

My Feedback: (1)

rog and pt are right. My first three or four flights were a little ragged, but when it gets seated it's a really nice little engine. I think the best prop for this engine is the APC 5.7x3, but I'm going to try an APC 6x2 the next time I fly it.

BSARGE

I got 5.7x3 on mine, and after about 5 tanks through it really screams....and thats just on 10% omega!

-Bill

chevy43

I never said anything about only 3 tanks. It had about 4 tanks of diesel run through it before I swithced it to glo. Also I'm peaking it momentarily not letting it run on that way - is that bad?

I've got some 25% and 30% to try tonight....

rainedave

My Feedback: (1)

Yes, back off several hundred from peak.

chevy43

Well I don't understand it but it runs a 7x3 at over 13k and the 6x3 at at just 15K. Acording to my caculator that is way more thrust from the bigger prop.

I have tryed 25% and it runs smotther and responds better to the throttle but doesn't have any more power.

Anyway a 7x3 turnine 13K is almost 20 oz of thrust which looks great to me considering the planes I plan on using this engine will all be less than 16oz.

flyinrog

My Feedback: (1)

We're not getting on you about the running or the thrust calculations..it's that you dont seem to be concerned about breaking in the engine properly,,either high rpm's or high load on the prop isnt good for a new engine....Rog

rainedave

My Feedback: (1)

I agree. It is ALWAYS better to break in an engine with less load. Dub Jett suggests breaking in non-ringed engines by running them at their rated rpm on a prop one size down. In other words, if the engine turns a 6x3 at 16,000; run several tanks with a 5x3 at 16,000. The you can move up to the standard prop and go for 16,000.

chevy43

Guys, I already broke the engine in on diesel before I started messing with glow fuel....... I'm positive it is broken in now anyway. I have run a bunch of fuel through and it doesn't seem I have damaged it - it runs great!

lildiesel

I have had the same experience with the AP Wasp with the RJL head --- wound up with a nice control line engine for a 1/2A trainer for my son last summer. One thing that did have some promise on the throttle front (until the weather got to cold to bench run outside at the beginning of the month) was to make a diesel disc from .015 teflon and use that in place of the gasket. That burned out (predicably) but the next thing I want to try when the weather is warmer is sandwiching the teflon between the contrapiston and a thin aluminum disk underneath it.