I see refences to some of the APC props but never any reference to the 4.5x3.5 4.5x4.0 4.6x3.0 and 4.75x4

Anyone use these? The APC site indicates they are marketed for 1/2 combat / pylon racing. I see the 4.2x4 mentioned on here frequently but not these other sub 5" props.

Good? Bad? Indifferent? Tower only lists the 4.75x4 so I am guessing they are not common LHS fair.

cheers, Graham in Embrun near Ottawa Canada.

Some interesting choices, I use props that come from the Ukraine or some place over there that are imported by Larry Driskill, My favorites seem to be the 4.6x3 or the 4.46x2.8 ones for my racers. I see maybe apc has a few that would probably work in this range, but like most apc props I have used, I break too many on landings, no matter where the prop stops, (I set mine to stop horizontally when the engine quits) the apc's seem to break even if they hit a knat on the approach. The carbon reinforced glass props that the combat guys use last so much longer for me. a big plus when you consider I rework my props and sometimes I get more than an hr worth of time invested on each. For the guy that likes the speed from diving runs though, I bet the apc's perform well in that part of the sport. I bet a guy would have to order these straight from apc though, and I bet they cost $4 or more each.

I think this is alittle O/T but The Glass Filled Nylon props are a lot stronger. They wont break near as much as the APC props do. Their is more of a selection of the Glass/filled Nylon also.

My little quest for the last couple of years has been to see how fast I could get a .049-.061 powered plane to fly. Flat out speed. I tried various carbon props available from Mike Hazel and Steve Wilk, these guys have an infinite selection of 1/2A sizes. None of their props were noticeably faster for me than the $1.83 4.2x4 APC, so guess which prop I buy 24 of every year? I have tried the other APC props, but they aren't optimum for the tiny stuff I've been flying. My smallest racer has 105 sq inches and weighs about 10-11 ozs. Every racer and speed fanatic has a bunch of different sized props laying around, because only GOD knows which prop will be the best one for your particular engine / plane application. The 4.2s don't break THAT easy because there is only 3/4 inch of blade hanging out from the edge of the fuselage. I think APC offers a nice blend of affordability and performance.

APC props came out the year I finally bought my first radio (1989). So, I've been using them since I've been flying r/c. At my club, it was amazing how quickly most folks started using them. Most of the seasoned pilots at my field talked about them like they were the greatest thing since working carburetors.

The next time a Tower coupon coincides with a purchase I'm going to buy four or five of the ones Graham listed. I've got my Sure Shark dialed in good and I'm getting very consistent engine runs with the reedy. At exactly 10.25ozs it's the best test bed I have for trying out these exotic APC's. It will be fun to spend a couple of hours running them back to back to find which one "feels" the best. FWIW, I hate the APC 6x2, on my airframes, anyway.


David

The 6x2 excels at 3D, trainers, combat and other applications where speed is useless and where max thrust is indicated.

Interesting comments.

I have looked at the props that Larry is selling and I think I will get a couple of each to try and a couple each of the APC. It looks like I will have to order direct from APC. Incidentally the price of the APC props I listed are just under $4 each - about the same price as the imported ones that Larry sells.

I guess some testing will be in order. But first perhaps I should state what my goal is - asking about props without any reference is a loaded question.

I have a hankering to build a 1/2a proto profile control line plane. For those that are not familar, these are speed planes built with a profile fuselage using 1/2a engines (that you could have guessed from the name) The basis of the event is a timed 10 laps from a standing start. So, not only is top speed important but so is acceleration. The planes generally have about an 18" wingspan +/- and 45 to 55 square inches of area with an all up weight of around 6 to 7 ounces.

Now, there is very little in the way of control line flying in the area that I live and it isn't likely that I will be attending the NATS or any other organized speed events this year. So, I thought I might push the idea of the event a little further. There is some talk about extending the engine size limit for 1/2a speed to .061 and with this in mind I thought I might create my own challange which I am for the moment calling the Hobby Shop 1/2a proto profile. In indoor free flight extreme lightweight models are the norm - 1 or 2 grams or less for some classes. One class that is popular is called the EZB. There was a published article called the Hobby Shop EZB where the idea was to build a competitive EZB using only commonly available materials from the local hobby shop - no ultra light, hard to get and expensive indoor balsa wood - just off the shelf from the local store.

So to take that idea and expand on it a bit, my Hobby Shop 1/2a proto profile will be built using on materials available from the LHS - no high tech equipment, no high price imported limited availability engines. Off the shelf balsa, dope, wheels, two line control, etc and using the now only easily available engine - the AP .061. and 10 percent nitro fuel.

That's my challenge hence my looking into the APC props as they are generally available from the LHS. (but it will be interesting to try out the props that Larry sells as well. Who knows, maybe the APC 4.2x4 will be the best overall?

Thanks for the input. Anyone else want to have a go? The more the merrier.

cheers, Graham in Embrun near Ottawa Canada

I am building a 1/2a proto too, I bet the 4.2 apc will be good for that because you can whip the plane for take off then you have 1.5 laps to get into the pylon or center circle. I ran a 4.6x3 glass prop on an AP and 40% fuel, it spun up to 29k then broke about 2 minutes later. I replaced the carb with a venturi. If I would have used milder fuel, maybe it would have made a few runs.
I will use the GZ .049 for competition or the Cyclon, Problem with that Cyclon is the lack of substantual beam mounting lugs for use in 1/2a proto
I think a "Club" class event that only allowed the AP or other non bb engines would be a blast to play in on the local level.

APC props are glass filled nylon... I don't understand what you are saying.

I built a 1/2A Proto back when the Cyclons first came out. I got the Cyclon from Doug Galbreath and it was a rear exhaust version (the only version there was then).

I ran Hazel's props because he had them in higher pitches than we ran in Combat. At that time the Proto record was 110MPH, or so, and I figured it was going to take at least 4" to 5" of pitch to be competitive. 4" @ 30,000 = 113MPH; 4" @ 35,000 = 132MPH and 5" @ 30,000 = 142MPH.

Since the timing is from a standing start you need to go a good deal faster top end to make up for the time used to accelerate.

I think my plane was (is) about 7 ounces. Were I to build another I would shoot for 4 to 5 ounces as I was not getting to speed nearly as quickly as the fastest dudes at the Nats that year. They were turning over a hundred and I was going about 90.

Here are some dusty shots of the plane. Toad, note how the mounts are notched for the Cyclon. I used a stiff, thick nacelle to make up for the rather thin mounts where I notched them.

I've never tried it before, so this is my first try, thank you for the pictures, it helps alot. I like what you did for the mounting, the thought of modifying my Cyclon case was causing me to lose sleep at night.
Kinda funny, I just ordered a .061 from Doug, I went for the rear exhaust, and I ordered 3 GZ from Zhou (I have not recieved the GZ's yet, man they are slow in china) And I made a mistake on them. The Cyclon I will keep as is and use it in pylon, but the GZ's I ordered the .061's not thinking I need the .049's for proto dang it!

Looking at the list, a few really interest me:

http://www.apcprop.com/cgi-bin/store...c=6a&product=+

The 5.5x2.5 sounds like a good reedy prop and it's only $1.83. It will certainly unload a little better than the 5.7x3 in flight.
The 4.5x3.5 would be interesting to try on an AME .061, I think.

Dave,

I'm using the 5.5 X 2 on my throttled VA / LiteHawk and you are right, it unloads and performs better than the larger props.

I am curious how your AP 061 broke? crank? connecting rod? I have seen your web page and details on the small engines. I take it your experiments with the AP are still in progress and you are having mixed results?

Seems I struck a chord with the 1/2a proto thing what with you building one and Larry having about with them before.

My intention is just something to mess about with as I don't envision attending any organized speed events - a challenge to see what I can get out of it.

I see from reading the NASS newsletter that the GZ and GS are quite popular in the speed circles - 1/2a speed now what was it 140+ mph and proto profile 120+ - wow!

Props have been ordered and tests will commence in a few weeks. Bench running is one thing, the proof will be in the pudding of course, running round in circles.

cheers, Graham

Cool Larry, thanks for sharing.

On Jim Bookers web site is a picture of how someone built a proto using a Profi which has a radial mount. There is always a way without having hack up the engine.

Looks like you used a bladder tank of some kind or was it straight pressure?

That AP, I tried to port it to the AME timming (which isnt much different) and make the port windows the same size of the AME (big difference here)
Upon carnage inspection, The piston seized in the cyl, with evidence of the coating of the cyl wall "melting" away from the top of the ports I cut. The lower end of the rod let go. Max rpm I got was 29,400 on the tnc tach. I was very anal about smoothing the edges of the ports after I cut them, and I was skeptical that the hard anodized cyl would not like to have the ports cut into. It seems I was right. The engine was not leaned out all the way when it broke either. I did this same porting excersize on a BigMig revlite cyl, That one has over 16oz of fuel ran thru it and it never did run up to where the AME revlites run for me. But The bigmig never seized either. I think trying to re-port the AP to run with the AME is probably not worth it.
Maybe I will try it again. My goal on the 1/2a proto is to enter a speed contest, I am about a 7hr drive from the L.A. california area and I think it would be a blast, plus I would like to see a good speed event anyway. I have never seen it done nor have I flown a speed c/l plane. Larry's plane looks different from what I read the rules to state. I thought they had to have a clear canopy? So I stole one from a Lil Jumpin Bean Kit I have lol
I probably should start over on my plane, larry's looks like it would kick mine into trainer status.
To get back on topic, I am going to try that APC 4.2x4 prop on my profile speeder. I'm going to be realy late getting this project done. I have to order some .049 parts to put in the .061's I already ordered.....I still feel stupid about that mistake I discovered this morning. DOH!

Toad, good luck and have fun. I've never tried speed, either....but it is awesome to watch. You might want to get warmed up with a slower plane anyway, those competitive lap times are pretty short.

I always liked the idea of CL Speed, but I really like to fly models and speed flyers don't generally log much airtime.

Toad, it had a canopy. Look at the first shot. There are some remains of a flat plastic canopy that was in a slot where a rudder usually lives. On this model I put the rudder on the bottom and the canopy on the top.

Graham, I used a bladder made of KT20 tubing and had it stowed in an aluminum cigar tube.

I just wiped off the dust and weighed the airframe and it is 5 ounces. For a really quick first lap, I think 5 ounces ought to include the engine. But at that weight the takeoff could be exciting dealing with the torque.