AP engines
 

I have no idea if this is the correct forum to place this question in or not. But I will submit it here and I am sure if I am incorrect I will be corrected.

Does anyone have any experience with AP engines? That is to ask about the running , starting, and reliabbility.


They seem to have a place for my type of flying.

I would appreciate all comments both good and bad.

I Am intrested in the new products now being offered by Tower.

That would be the .09, .15 & .061.

All comments will be appreciated!

RE: AP engines
 

You got the right place al'righty!

RE: AP engines
 

I ran the AP .15 on 15% and 20/20, ran ~ok~ on the 15 powermaster but more reliable (better low end) with the 20/20PM. I got it mainly for the rear muffler to hide inside a nacelle more. I was more interested in appearance than massive vertical.

RE: AP engines
 

I had the 15 for a very short time. Only three flights. It seemed to start and run well. I think it was broken in when I received it. The only thing I noticed was a very small hicup in the midrange, but I never tried to adjust it out. I would buy another.

RE: AP engines
 

Apparently the quality differs from engine to engine. The few that I've ran across (with my car[>:]) weren't much good. AP was a Chinese knock-off of the early Norvel. Since then, Norvel has made drastic improvements and is a better value.

RE: AP engines
 

Must be right, as Norvell's run in the N E Gremlin classes.

RE: AP engines
 

Most 1/2a folks prefer Norvel over AP (and to be honest so do I) but the AP Wasp is a good engine. I've had an AP .061 Wasp for the past year and it's an absolute champ! No, it's not as powerful as the Norvel .061, but it's always started right up, needs little maintenance, has survived countless crashes and it always starts right back up and runs and runs and runs. It turns around 15,500 rpm on a 5x3 prop, and around 13,000 on a 6x3. It's only a few bucks cheaper than the Norvel .061 so price is not a reason to buy one.

Common opinon about AP on this board is that AP quality control is not so good. EG, some are really good and some are really bad. Mine is a solid, reliable engine!

RE: AP engines
 

Eroc, a good seven dollar Surestart will turn those numbers with the low compression head! Pick up some MORE RPM's by changing the head. I think my Norvel BM .061 turns a 5x3 up past 20k. (22?) We're talking a third more power in the Norvel. You can pick up a TD fairly cheap these days too. Heck, they're only fifty bucks brand new! More POWER!:D

Kinda hard to beat the value of the seven dollar Surestarts though. If they'll ship them! I ordered some more a long while back and haven't even got an email.

RE: AP engines
 

I pulled a couple of run sheets from last year, I never did test the BIG MIG, but here is what I got on 30% fuel with an AP .061, and an AME .061 for comparison. I have owned 2 APs and they have run fine for me. I think they are about 1000 off from a BIG MIG in most cases, I just never recorded a BIG MIG run session or else lost the sheet.

AP
5x3 COX 20,000
6x3 MAS 16,300
5.7x3 APC 19,200
5.5x2 APC 22,500

AME
5x3 COX 21,200
6x3 MAS 17,900
5.7x3 APC 21,200
5.5x2 APC 24,000

As you can see, the AP is 90% as strong as the AME and probably 95% as strong as the BIG MIG. At $29 I decided to take a chance on one, liked it, then ordered one more. They have worked out well for combat, even used one on a HALFWIT. Pulling out the carb retainer screw that cuts across the intake tract [and restricts airflow] and JB welding the carb into the case [instead] is worth some rpm, but the above test was with the carb screw in place.

RE: AP engines
 

LeeMRC- what size were you looking at.... is there a plane in mind for the motor? The reason I liked the AP was the rear muffler, but that don't come on the .061 . And I hear the .09 is weak for hard flying in a .10 plane, but looks great inside a cowl. I had a .15 sized Texan that the AP 15 fit tottally inside the cowl, just a small hole for the igniter, an exhaust tube, & some cooling outlet slit. If you are looking at the smaller guys, I'd go with the Norvel 074 over the AP unless you really like the rear muffler more than power.

RE: AP engines
 

CP, did you get any TD .049 readings? I wonder how it compares with an AME or bigmig.

RE: AP engines
 

40 flights out of this AP 15 in a mini funtana. It weighed in at 25 oz and went like a champ. Flew best with an 8x6 that I cut down to 7.75x6. The engine still lives.... the funtana is decomposing. I'm looking for a new airframe for it.

RE: AP engines
 

HI PATRICK, I did get some TD readings, but they were with a bone stock model that was very average. Good for comparison, but considering how easy they are to hop up, the results were way down from what we know they can do. Sometime, you should get some readings on the KB to add to our data base.

TD
5x3 COX 22,000
6x3 MAS 16,000
5.7x3 APC 20,000
5.5x2 APC 21,500

As you can see, the lack of cubic inches and torque bogs these engines down [compared to .061s]. Too bad the 4.2x4 APC came out 40 years too late, alot of guys never knew and will never know what this engines' potential is. A comment was made about some guys still running TDs in pylon, but not able to keep them together. I wonder if they're still running stock weight pistons? If you combine that with the DAVIS DIESEL crank, should be bullet proof into the high 20s. Even with just stock cranks, I'm still waiting to see my first light piston COX engine come apart.

RE: AP engines
 

I'll have to retest my AP, but on 25% nitro and 20% castor but I'm pretty sure I'm turning around 15k with a 5x3 - maybe my AP isn't so good after all... [X(] Then again, I'm sure you guys know a few engine tuning tricks that I don't.

PT - I've considered picking up a Surestart on more than one occasion if for no other reason than the price. Worse case I can give it to my brother for parts as he really loves Cox engines. Me, not so much...

RE: AP engines
 

Eroc, don't buy one! Not the briar patch!:D

CP, you've given me something to think about. Your numbers with the 5x3 relate very closely to what happened with my delta. On the TD I was using a 5x4 Cox and was getting closer to 24k (maybe over?). The smaller blades may have lessened the load enough to explain the RPM increase. The 5x4 and the 5x3 don't look much alike. The 5x4+TD was REALLY hauling the mail! (BTW, this was the big delta)

RE: AP engines
 

PATRICK, your TD was running with the best of them, There is so much performance variation with these engines that it is impossible to tell some one what a COX this or a COX that can do. 24,000 with a black rubber 5x3 is actually very good [70 mph] but with a 5x4 you must have been in the 90s.

Too bad COX didn't take the extra machining step to lighten all the pistons in every engine, I think it would have paid off with longevity and performance, which would have helped build them a better following. I would venture to say that the vast majority of guys who ever got there hands dirty on a COX engine were turned away from 1/2A. I've seen it all around me, and they nearly did it to me also, way back when. When I finally got my hands on a real engine [FOX .15 and McCOY .35], I thought I was in heaven!