kirknik

I'm gonna start my first pattern plane. GP Tracer with an OS FX46 engine. Although its my first attempt at pattrn, I wanna be serious about it.
Retracts or not is the question.

What do yoose guys think?

NCC-1701

I recommend going with fixed gear for two reasons:

1. Weight. The Tracer is a great 40 sized airplane. However, due to it's small size, the added weight of the reracts will increase wing loading and decrease vertical performance noticeably.

2. AMA Precision Aerobatic rules for 401. I am assuming you plan to fly Sportsman class. If so, the rules for Sportsman require that the aircraft either have fixed landing gear or the rear, if retractable, must remain in the down position for the entire flight.

Since you will not be allowed to raise the gear anayay, go with fixed so you can get your Tracer finished faster. Then you need to practice, practice, and practice.

Good luck


Rob

Check out the NSRCA website for good info on pattern flying, including contest listings.

http://www.nsrca.org/

JimTrainor

I am building one now - with retracts. Mainly because I think it's cool. (I am aware of the gear down rule.)

I just weighed the parts:

Stock Gear: 2 x 1.0 oz = 2 oz
Light Wheel 2 x 0.25 oz = 0.5 oz
Total = 2.5 oz

Hobbico Retract incl axle 2 x 2.0 = 4. oz
Light Wheel 2 x 0.25 oz = 0.5 oz
Retract servo = 1.5 oz
Total = 6 oz.

So you're adding at least 3.5 ounces. With effort, you might be able to shave an equivalent amount elsewhere.

Get light weight wheels!!! I have another set of wheels here that weigh a full ounce each. Big difference.

I have the wing together now - with retracts in *and* the heavier 1 oz wheels in. I also have a GP Stick ARF (40 size plane) wing here. The Stick wing is fatter, same span but constant cord, and of course has no gear. It feels noticeably heavier. I expect the Tracer will be a bunch lighter than the Stick when all is said an done.

For reference, I ran the stick with an OS46FX, tower muffler, and a 12x4 prop. That combo had unlimited vertical... or at least so much vertical that I could no longer control the plane accurately - to maintain straight up - due the loss of perception as it went higher.

I will run the tracer with another 46fx and a Jett Stream muffler and I'll probably stick an 11x5 or 11.5x4.5 on it - that I expect will turn 14K+. I don't expect to have any power problems. But I am pushing the engine.... it really screams.

If you run the 46fx with the stock baffled muffler it might be a tad weak with or without retracts. Baffle out would be better. Or get a Tower/GMS/Hobbico muffler (they're all the same).

Finally, if you go with retracts you must use 2 inch wheels. 2.5 inch won't retract fully.

bla bla

I'm just havin' a ball without retracts... can't even think about going backwards unless I went into SPA... just to much trouble and fiddling around.
Cannot tell the difference between an aeroplane with retracts or one with fixed. I like 'em down...at least I know where they are!

kirknik

Thanks guys.
As the 'coolness' factor is very important, I think retracts will be in order.
Thanks Jim for the comments on the FX 46. I think I will look into a performance muffler for it. Maybe a tuned pipe or something.

JetAwithPrist

Kirknik,

I have a tracer also and have retracts in mine. I am sure they add some weight but it does look cooler. Other added weight with the retracts are the linkage, the wheel wells, and what you use to finish the wheel wells (i made mine from 1/16 ply and painted them). You also lose some of the cleanliness of the wing from having a big hole in the bottom which would matter more inverted. The wheel wells are kind of time consuming to produce but finish them well because they get oily from exhaust. If i were to do one with fixed gear i would use a one piece gear from the fuselage instead of the wire gear just cause i think it looks better especially with wheel pants. I would check out the balsa (some of mine was pretty heavy and poorly die cut) and consider replacing it. I emailed GP about it and they never even answered me.

One thing to consider as far as the tuned pipe is concerned is that the muffler points straight at the wing LE with the stock (inverted) configuration. I put a tower hobbies 46 muffler on my 46fx which does fit but if you wanted to add a tuned pipe you would probably have to mount the engine differently. Oh, and i used 2.25 inch wheels because 2 inch are just too small for where i fly (rough asphalt) and they do fit nicely in the wells.

JimTrainor

oh they fit? great. It looked to me like they would bump up against the top sheeting (tops not sheeted yet on mine).

JetAwithPrist

Yes, they fit on mine anyway, although i cant exactly remember but i think i may have made my wheelwells a little bigger than on the plans. I know that they went up against the spars at the back. They have enough room that i wouldnt be too worried about debris or anything jamming them up. As far as hitting the top sheeting if it hit you could just adjust that out.

Blixsim

Had a tracer and its a great flying plane ( I say 'had' cos it flew off into the blue yonder due to a momentary loss of concentration and its small size ensued that I coudnt see if its coming or going.)

Had retracts and can definitely say you can 'feel' its weight. Suggest to go fixed carbon undercarraige with ultra light wheels. You can then put the extra money saved towards a tuned pipe. The 46FX has plenty power altho I feel the tracer needs the extra bit gained from the tuned pipe. I performed some cosmetic surgery to the belly to ensure the pipe fitted nicely out of site (almost).

A great flying plane. Am currently building a 60-size light version from enlarged plans so that I can at least see plane.

JimTrainor

Tracer builders:

How did the plane balance? Tail or nose heavy, and how much weight did you add to balance it?

Thanks

JetAwithPrist

Mine was nose heavy, but not tooo bad. I put the battery under the wing bolt plate and havent added any additional weight. I may add a little weight to the tail to help trim it out in the future.

Cdallas2

Kirknik,

I just checked my MAAC rulebook and can't find anything that says you can't use retracts in any class. So unless you plan to enter contests south of the border you should be okay.

JimTrainor

Mine is quite nose heavy. Started out needing three ounces of lead to balance.

Moving the rudder servo back to the tail, the battery and receiver into a small compartment behind the wing, swapping out my nice aluminum spinner for plastic, and using a wood prop balances it without lead.

That will leave it at about 5 lb 11 oz assuming 5 oz for the covering.

Light covering (transparent monokote?) shifting the engine back 1/2 inch, using NiMh batteries, and a micro servo for the throttle would get it under 5 lb 8 oz - exactly at Great Planes upper limit.... not worth the effort/expense.

This is with retracts.

I wasn't terribly cautious with the glue, and didn't consider swapping any of the heavier bits of supplied wood, so lighter is probably not too hard to achieve.

Cdallas2

Jim,

How was the wood in your kit. I'm building one now and found that the wood for the wing was perfect, but the wood for the fuse was awful. I had side fuse side pieces that I thought could have been spruce. What really caught me off guard until it was too late was the all the fuse die-cutting was wrong. All the sides and formers were slightly different than the plans.

I've built this one with fixed gear, but I've saved all the templates and I might build a second one with retracts. I'll also cut out the fuse formers as per the plans though. It will make it straighter and lighter to boot.

I'm planning on flying mine with an MDS .46 but if you guys are saying it's that far nose heavy I might have to get something a little lighter. I'm thinking along the lines of a TT .46 or a GMS .47 but I'll have to wait and see.

JimTrainor

The wood in my kit was similar. I don't know if I'd say the fuselage wood was awful, but it was definitely hard and heavy. Perhaps they (GP) planned it that way. i.e. hard balsa rather than light ply. I don't really have enough experience to say whether it was better or worse than typical (or required).

The fit of the fuse peices was not exactly precise on mine. But it really didn't cause any problems.

I think one could shave a fair bit of weight off the fuselage by, perhaps, stick building it. ... perhaps next winter.

MDS 46... you mean 48? Is it really heavier than others?

Cdallas2

Well I thought it could have been better. To say the least I did use it in the end.

Actually it is an MDS 46 (it's a little older) but had never been run. As far as the weight goes - if you were to pick it up you could easily tell how heavy it is.

JetAwithPrist

i would classify some of the wood in my fuselage as aweful. It was very heavy, wavy and innacurately cut. I took the time to inform GP about the lack of quality and they didnt even give me the courtesy of a response. I am quite sure i am not the first person to have this complaint so to blow off someone they know has a legitimate problem says a lot about their customer service to me. No more GP kits in my shop any time soon.

Cdallas2

Even with the not so perfect wood and nose heavy planes how does (or did) everyone think of the flying habits. Is thier anything we should consider before the first flight?

JimTrainor

Mine won't fly until May.

Blixsim

I found the biggest problem with this plan to be its small size which makes it difficult to see correct orientation once on the run. Suggest you keep colours bold to ensure it stands out. It does get quite small rather quickly.

regards
Hedley

Cdallas2

As far as the small size goes, why is that any different than any other 40 sized plane?