R/C airplane weight Question

Well Thanks Larry , I got it for 20.00 already built w/ I think it had a BW on it ( swap meet ) next ...

My 3 channel R/C Toucan has 800mm wingspan and weighs around 500 grams when the tank is full. It flies with a normal 049 COX Product engine rather well but with a TD051 it is a ball to fly.



If you take off from its landing gear I would make sure it will have long enough runway like 5m or so. I hand-launch my R/C birds because of the grass on the field.

getback wrote:I have this airplane I put an older  conquest 4 FM transmitter / receiver and Battery pack in with mini servos and I am thinking its going to bee heavy for the TD .049 I have in it , I need some input before I put it up ... 2 channel ,36" WS ,26" fuse length and the best I can come up with bathroom scales is 1.25-1.5 Lbs. I have it s CG about 1" off LE here is some pics.        Thanks , Eric

I would think 16 ounces maximum. You didn't say what the total wing area is? Chord times average wingspan. There is an average number for small planes oz./sq. in. or something like that. Something happens when you get old, but I can't remember what it is.
   P.s. I hope someone else answered this already.

Happydad. Still tired                

Thanks guys sorry the width is 7"x36" core is 3/8" its a thin wing ?/ I cant find the cow Q later ?? It looks like a semi floater with the right engine Or load ?

getback wrote:Thanks guys sorry the width is 7"x36" core is 3/8" its a thin wing ?/ I cant find the cow Q later ?? It looks like a semi floater with the right engine Or load ?

sorry. I've been trying to get to the garage for hours to weigh a couple of my electric planes and subtract the extra weight of the extra large battery and the huge electric motor used in days of old, astro 05 motor and 6 cells sub C battery pack.

back soon

edited 10:12p.m. PST 9-5-15: to add data from my electric, glider and would be Cox gas plane.

 My old electric Astro sport has a wingspan of 38 inches, chord of 8 inches = 304 sq. inches wing area. weight with the old astro .05 electric motor and 6 cell sub C battery pack, and radio = 36 ounces. It flew well, but fast only, no slow flying it was to skittery.
On the other side my favorite slope glider had a wingspan of 40 inches with a chord of 7 inches for a total wing area = 280 sq. inches. It weighed 14 ounces with radio and a AAA battery pack for longer flights. This was a small plane. It flew fast in heavy wing and slow in light wind.
  If i were to put a Cox gas engine in the Astro Sport the wing area would still be 304 sq. inches, but the engine, plane  and radio weight would now be only 17 ounces. The electric motor and battery weighed 18 ounces together. Glad the old electric motor days are gone.
   Hope this helps.
happydad  still retired, and still trying to help.

Thanks balogh That's 1.1 # 31.5 " w/s ,,, I need to find a better scale the wing area is 252 " and with a thin thickness wing I don't see a lot of lift Happydad those 4 AAA batt. is were the weight is you really need a big plane and power to fly these old systems I will have to give it more consideration I don't want to destroy the poor lit. baby Eric

There are much lighter battery options. The LiFe batteries are an example. They're 6.6V/cell, so you need to make sure your receiver can handle one.

What model is it? I see your using a tank-mount for the Tee Dee. Was this model designed for a reedy? Is the c/g where it's recommended to be? There seems to be less dihedral in the wing than I'm used to seeing in a elev./rudder-only model.. but it's hard to tell from the photos. Ace RC made "Grasshoppers" in two different sizes.. 43.5" and 52.5". Both were designed for Cox .049 reed-valve engines.. and both specify a 20oz. weight. The 43.5" span version is 214 squares.. and the 52.5" version I believe is around 260 squares. Both wings have much less chord-percentage/span than your wing does. Your wing; having a thin airfoil section, may have a slightly positive angle of attack built into the wing-saddle, to generate lift in the design?

You might end up having a handful with the Tee Dee if this kit was designed for a reedy. Of course.. you could set the needle rich for the 1st flights. This model has trainer-like looks to me.. but I don't think it'll fly like one with a Tee Dee. Is that a 6" prop you're using? I'm just tryin' to help you avoid the "OH S#%T" feeling when you get it in the air.

Well, the 20-24 ounces you quote are on the high side, but since you're using a TD it should fly okay.  But, it won't glide really great.  It'll come down moderately fast rather than floating, but so long as you have the c.g. right it'll come down smoothly instead of falling out of the sky.  If I remember correctly, the S-Tee wing was a 7"x36" wing.  The wing in the picture sure looks a lot like a S-Tee wing.  The S-Tee and Q-Tee had relatively thin wings.    The S-Tee was originally designed for a ready to fly weight of 18-24 ounces, which was normal for the mid 70's, so you're at the upper limit of that design.  I flew my first Q-Tee with standard size servos and a AAA pack.  It flew okay with a Bee engine, but it didn't float after the engine stopped, and the glide was pretty fast coming down.  I had 200 flights on it when I gave it away, so that wing is definitely flyable long term at that weight.  

Look at this S-Tee plan and see if the wing looks the same.  If so, you can take your c.g from the plan for your first flights.  A smaller battery would be great, but if you don't have one, I'd give it a try with the one you have in there anyway.  Just look for a lighter battery as you fly what you have.

The Cutie Mark

getback wrote:Thanks balogh That's 1.1 # 31.5 " w/s ,,, I need to find a better scale the wing area is 252 " and with a thin thickness wing I don't see a lot of lift Happydad those 4 AAA batt. is were the weight is you really need a big plane and power to fly these old systems I will have to give it more consideration I don't want to destroy the poor lit. baby  Eric  

This electric plane was last flown in about 1986. The state of the art batteries were 1/2 sub C cells for the Astro .05 motor.
   The sub AAA batteries were for the current sailplane and they weigh about 1 ounce.
  The Astro .05 put out enough power to almost make the Astro Sport plane go vertical, all 30+ ounces, almost. It was a stunt plane and I could do axial rolls with rudder and elevator.

Happydad  

That's not it Mark both the wing and stab/elev. are solid here are some better pics . I am pretty sure it had a Black Widow on it the man said it was pretty fast but I don't know what radio equip. he had in it ????///         Pay no tension to the mess my son hasn't cleaned up yet Eric

Ah-HA!!!  The side pictures gave it away.  It seems to be a Honker Rocket without the turtledeck.  See the plans and building article here.  Also, the RCM logo sticker on the right wing reinforces the supposition of it being an RCM plan.  The article shows a flying weight of 20-25 ounces, so you're right in line with the original design weight.  

Also, make sure you use some foam to isolate the receiver from airframe vibration.  Bad Ju-Ju.

The Eureka! Mark

Thanks !! Mark That is it we have a winner !! looks like smaller batteries are in order and change engine to BW power , my experience with RC is low and not ready for all out haul ass model And the foam thanks for reminding me . yea that batt. pack want go through the cockpit hole so I'll look for some replacements . The guy I bought it from must not had planed on racing it or he would have put the Ailerons in force to make it turn and not skid so bad but that's OK for now . Eric

Getback,

I was asking similar questions a while back on my Ace Whizard. With my old Focus 4 equipment, I was weighing up at 24 ounces, and was very nervous.

I was able to shave 4 oz. off of the all up weight by replacing all of the onboard electronics (battery, receiver, 3 servos) and going to foamie wheels instead of rubber ones. The wheels alone saved me an ounce of weight.

The Whizard is pulled around by newer 049 medallion with muffler throttle, so I honestly don't think you'll have much of a problem with a TD on your Honker.

Thanks for the reply VU... I am concerned with the CG though way to forward and I cant even wrap the batterys with form they are so tight , with one bad landing they would probably come through the fuse The TD has a 6x3 TD prop so I could run it rich a tad and would keep the speed down till I can get it figured out . getback

getback wrote:Thanks for the reply VU... I am concerned with the CG though way to forward and I cant even wrap the batterys with form they are so tight , with one bad landing they would probably come through the fuse The TD has a 6x3 TD prop so I could run it rich a tad and would keep the speed down till I can get it figured out . getback

What I have done in the past when I couldn't get the battery through the former with the foam on is to cut the foam into smaller pieces and put them in the bottom and sides to make a "rubber room" in the nose, and push the battery in place. Then I stuff a piece of foam on top of the battery. It held in place pretty well for me.

The Crazy Mark

No that's foam isn't the prob. its the opening to small for the batt pack and the CG being too far foreward already .. I will have to see I may can make a cradle from a couple popsicle sticks and put it over the servos I don't even like that but .. later I will pull the plane back out and look again and reck. that CG . get back to you before I do something stupid and see what you think . I have 2 hinge jobs I want to get done today also !! Eric

Eric, have you thought about reconfiguring your RX battery-pack arrangement from a flat-pack, to a square AAA one? That would be cheap enough to try at least.

There are different connector options..




to arrive at this configuration..




4xAAA NiMh 1000mAh option

You may be able to open-up (hog-out with a Dremel's rotary-rasp) the forward-bulkhead.. enough to position the battery more forward.. thus addressing two issues; a too-far fwd. cg, and the overall fit of the pack. If the hogged-out opening is sized correctly, a foam-rubber wrap around the pack would help to hold it in position when it expands against the bulkhead. As for foam-padding.. the newer type "shelf-liner" is a very thin rubberized-foam mat which is spongy.. and could be wrapped around the battery-pack until it fits snug.

This is a AA holder.. but you get the idea. The AAA holder is a lot smaller.. and I'm sure you could make room for it.

You know.. either engine could be fitted with an exhaust-throttle cylinder-set, if you had one.. just sayin'..

roddie wrote:You know.. either engine could be fitted with an exhaust-throttle cylinder-set, if you had one.. just sayin'..

I have the R/C sleeve and cylinder-R/C sleeve sets, new and old. So do ESP and coxengines.ca (new). PM me for my info.

happydad   (Labor Day)

Thanks guys , the battery arrangement is something to think about and I have throttle rings muffled or not , before I even think of that I need to get this figured out ran out of time yesterday my hinge job on the .020 Zero became a repair before I can finish stitching May be today I have a lot I have got behind on that I have got to get R done stuff then play . Throttle sound better an better but batt. CG first Eric

I think you'd be fine, back in the early 80's i had powered this plane with a golden bee, two full size servos and a 500 mah battery, barely keep airborne, added a Tee Dee and it flew great! Later swapped out battery for 250 mah battery, even better.

I think the plane will fly just fine, that's what they used to weight in the 80-ties and they flew just fine. You won't need any throttle though...

The spring held batteries are dangerous though, as the batteries can shift and disconnect. You'll be much better off with a soldered battery pack from e.g. Radical RC (RX battery packs)

Here is the plane I learnt to fly on, used a two-channel standard radio and a BabeBee engine, 26" wingspan and about 20oz ;

Kris beat me to it but I'll say it as well, I would steer away from any of the dry cell battery holders, They don't take kindly to vibration and have a notorious reputation of either breaking or a battery pulling away from a contact and causing power loss bad thing with a flying model.
If you need room and less weight, I would go with a 250Mh flat pack. That's what I use when I build small models.
(Bandit)