AP Wasp .061

Tell us what you do to get the best performance from your engines.

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sgilkey
Posts: 2351
Joined: Mon Mar 19, 2001 8:26 am

AP Wasp .061

Post by sgilkey »

All my testing to date for Limited 1/2A has been done with Norvel .061 and Cox .051 engines. I finally gave in to temptation and bought an AP .061 to make some comparisons. I have no photos for this thread, the AP looks like a clone of the old pre-Revlite Norvel .061, with a few changes. Some of these changes I think are actually better.

CARB: similar, but retained with two screws like a "normal" engine, whereas the Norvel is glued in. some pros and cons to this method. I just loctited the carb screws in place, no other changes.

BACKPLATE: o-ring sealed which SEEMS nice but i think the seal design is poorly executed in that the o-ring seals against the back of the case, rather than in a chamfer. therefore the oring gets squished and wants to ooze out the joint between the b/plt and case if it is tightened firmly. as the oring ages and takes a set, i am concerned this joint will develop a leak, but for now it has worked OK. If i were smart i would have chamfered the case before reassembly. Next time

HEAD: same design as the old pre-revlite "cold" head, though the instructions say it is a hot plug. what i mean to say is the clamp and plug are dimensionally interchangeable with the old "cold' head. the engine can be converted to the Norvel Freedom XL plug is the Norvel clamp is also used. Or the Galbreath/Nelson or Cox heads will also bolt up. One aluminum head shim- not three as in the Norvel, so adjusting compression is not as easy.

CASE: the crank runs in a bronze bushing instead of the aluminum of the case, as in the norvel. I really like this as I have siezed many Norvel cranks (25 and .061) to the case, so the bronze bushing looks like a winner to me.

Engine was prepped as per my Norvel engine prep thread, broken in on test stand with Sig 25% nitro Champion fuel. Engine runs very nicely and throttles well. The HS needle is finicky as you just touch it and the mix changes, however once making an adjustment it seems to hold it well. Break-in went smoothly. After 8 short breakin runs, engine tached 19.2 on APC 5.7x3. This is a good 1k down from my Norvels but may improve with more running in, who knows. Also some difference may be attributable to atmospheric conditions, it was very humid.

overall i like the AP and think it looks like a good alternative to the Norvel which is currently hard to find.
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boiler
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Post by boiler »

Scott,I made a mod to my AP. I got some O rings and put a piece of nylon chiffon over the carb to keep sand out. It seemed to work well. I got the idea from the used Norval that I got which had a fine mesh screen over the carb. I put some on my B and SSC ships as well. We'll have to wait to field test them. I also found a nice little travel pack of Q tips to help clean out junk if the nylon fails. I'm glad you only found one shim in the AP. That's all I could find and I thought I messed up because everyone was talking about 3 shims. The used Norval that I got only had one shim made of copper. The Norval has a head on it that is threaded for a regular plug. I have two complete open 1/2 A planes and a 3rd about 90% complete. I've used the phencepost material for the throttle servo mount as well as skid. I've use a couple more small pieces for arrow spacers and a small chunk under the wing for the radio and battery protection. With the 32 inch wing it weighs 16 ounces and with the 40 inch wing it weighs 18 ounces. I also have one complete scale 32 inch wing p-40 that weighs 16 oz. A second p-40 is about 90% complete and I have the wing for a Zero done. I built 5 Pirahna wings to use on my open/limited B planes and am completing 3 different bodies. One basic Pirahna, one Phencepost, and one twin aluminum rail (Battle Axe). I'm using the Pirahna wing rizor on all three. In a couple of weeks everything will be ready and I can build a couple of Gnants and start repairing the big Ultimate Bipe.
sgilkey
Posts: 2351
Joined: Mon Mar 19, 2001 8:26 am

Post by sgilkey »

Bob, the AP instructions state you can adjust compression by adding shims but the engine only comes with one, unlike the Norvel that comes with three. there is p/n for the shim on the AP parts list.
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