E-flite PT-17 balance

[doctormike]

This is a beautiful plane, but, even with a 3300 battery full forward it still needs 3oz. added to the nose. I know it has a stubby nose, but it seems they would have added the necessary weight at the factory or, at least, mention it in the manual. Have any of you guys bought one of these? Doc

[RRHandy]

I have one Doc and had to do the same thing to mine, I don't think there is a plane out there that the manual mentions adding to balance that I've seen yet. :Straight-Face:

[doctormike]

Thanks. How does it fly? Doc

[TiredIronGRB]

I've got one and use a 2200 all the way forward with no weight added, it's a tad tail heavy but flies great.

[doctormike]

From this, I can only deduce that the manual cg is incorrect (as usual). I put 3 oz. inside the dummy engine cylinders. From what TiredIron says my maiden might be really nose heavy. And I was worried that all the scale work (ignition harness and valve push rods plus paint and a scale prop) on the radial engine would make it nose heavy. Thanks for the input. Doc

[TiredIronGRB]

I have a wood prop and heavier prop nut on mine and I hate those battery trays so I take them out.

[andre]

Same experience. I've not added nose weight yet but it flew a lot better with a 3S 4000 vs 2200.
I've dialled in some down elevator to see if that helps since it seem to fly ok with SAFE on.

[doctormike]

I finally maidened mine. Needs a lot of down trim, even with 3oz. in the engine and a 3300 batt. Once I get it trimmed well, it'll be a great little flyer.:Cool: Doc

[F22trainer]

From this, I can only deduce that the manual cg is incorrect (as usual). I put 3 oz. inside the dummy engine cylinders. From what TiredIron says my maiden might be really nose heavy. And I was worried that all the scale work (ignition harness and valve push rods plus paint and a scale prop) on the radial engine would make it nose heavy. Thanks for the input. Doc

Actually it is correct, however it needs to be at the forward limit to achieve a neutral balance - it it a narrow envelope and anything aft it just sits tail low. I still needed 2.5 oz. in the cylinders and some down elevator. Now I also checked CG both inverted and right side up on a stand - never fingers - and found it much much stable on the stand right side up.
She flies very scale and behaves nicely.

[RichSam]

I am new to the forum but just purchased this aircraft and was wondering, what are you using for weight?

[fhhuber]

I am new to the forum but just purchased this aircraft and was wondering, what are you using for weight?

You can use just about anything... I like to use bird shot (tiny lead or steel balls used in shotgun shells) The lead it getting harder to get.

You can mix it with epoxy or other glue and then pour it into a depression in the foam or a space in a dummy engine cylinder or wherever is convenient to get the CG right with minimum added weight.

another option with some models is a heavy brass "acorn" prop nut or a weight that bolts on with the propeller and is hidden by the spinner. the "semi-scale acorn" nut that comes with the Dynam model is aluminum. A brass one would weigh more than twice as much. (but may be hard to find one that looks right)

I personally have always balanced all models on fingertips, until I made one that was 22 lbs (not easy to balance that on fingertips), which I hung from a ceiling hook and used the plumb bob method to find CG.
The plumb bob method will find the CG in 3d space rather than just fore-aft that we typically accept.
You CAN notice the difference in how a model performs when you move the CG higher/lower or side to side.

[boomer108]

I am new to the forum but just purchased this aircraft and was wondering, what are you using for weight?

Welcome to the Squawk RichSam!
.
.Most hobby shops that carry rc planes will carry self adhesive lead weights and Motion Rc carries them. They are made by Great Planes and come in 1/4 ounce 7 gram and 12 squares per package. They are easy to use and remove. I use them all the time.

[fhhuber]

You can also get self-adhesive tire weights from Harbor Freight (or just about anywhere that does tire mounting, if you ask might just hand you some). Essentially the same as the Hobbico/Great planes or DuBro (and a few other brands), but at far lower cost. The adhesive backing for automotive use is usually better.

[fhhuber]

Note: I have the entire set of discontinued Flyzone appx 1/10 scale WW1 planes. (appx 28 to 35 inch wingspans) Every one of them needed nose weight from 1/2 oz to 2 oz. None said add lead or anything to get proper CG. They just list the CG. (usually wrong, listing it too far to the rear for stall recovery)

And many other models...

Pretty much normal for them to say where the CG should be, but not how to get there..

[F22trainer]

Steel shot in fingers of a latex glove 3/4 - 1oz,avg per finger, or use a small mixing cup, measure what you need to balance on the stand, then mix some epoxyand stir in the bird shot. It sticks to whatever you pour it into.
Buy or make a balance stand, fingers should only be used to double check after a repair or such at the field. I always mark the CG range on the aircraft, usually with a Sharpie.
I take all the remaining bird shot and fill small Zip Lock Snack size bags (double) and use them as workbench weights. Great for when you are covering wings / fuselage/ or other parts during a build when you need both hands and a clamp is too risky for damage or just plain oddly enough shape a clamp is impossible.

[AirHead]

You can also use stick on wheel weights used for tire balancing. Usually lead or lead alloy. Automotive stores or tire sales departments have them....

[Steelon Steel]

I got my plane about a month ago and just built it up. I was surprised you guys said it needed so much weight as takingnthe fuselage assembly out of the box is was very nose heavy.

well after some digging and checking out the engine cowl to add weight I found my jugs were not hollow, they’re now filled. I put my fake radial on the kitchen scale. It is 250 grams or 9 oz. yes nine ounces.

It seems they came out with an amended product. Can’t wait to fly it.

[Steelon Steel]

I test flew it without safe enabled (because I am too ignorant setting up my channels). A bit sporty! Iirc I flew on 100 rates and was overcontrolling it. Some moderate porpoising that can probably be dialed out on the horn with a half turn on a calmer day.

I did get really nervous flying it like that, I got a handle on it, then flew a couple practice approaches without touching down, then came in under power, flying her in instead of the glide and plop to avoid the nose over. I nosed over lightly at the end of the rollout. No damage.

Since then I revisited the Safe setup with tech line help. Should be good now to ease the transition from the cub.

[skillett]

Well I have one also and use pennies. place a zip-lok bag and start dropping until tail comes up and nose goes down and fuselage is level. I have Calypso glider and used two quarters, nickels, and finish out with pennies.

But I would like to find some stick on lead weights. BeeBees would be good if you can find those with lead.

I dont have the all yellow, but blue and yellow and would like to know if you guys are having trouble stuffing in the batteries and wires just behind the engine. It's almost impossible for me.

Jimmy

[skillett]

[QUOTE=TiredIronGRB;n100011]I have a wood prop and heavier prop nut on mine and I hate those battery trays so I take them out.



[/QUOTE


ONE BEAUTIFUL PLANE I'LL SAY. Nice job modeling.