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I weighed some of my models and the weights seem a little on the heavy side. The weights are as follows: the rubber models are without the rubber.
mulvihill (my design) 5.5 oz.
Ray Smith Mulvihill 3.5 oz.
Maverick 1/2A gas TD .049 with tank mount 7.0 oz.
Starduster X TD .051 with tank mount 7.0 oz.
Dragmaster classic A2 10.5 oz.All models are balsa with tissue and dope except for the Dragmaster which has Polyspan on the wings.
Any comparisons and suggestions are appreciated.
Thanks,
EdThe Mavrick and Starduster compare favorably with my 1/2A T-Bird at just under 7 .oz There are lighter T-Birds around, but they don’t hold up too well.
To get really light requires very judicious wood selection. That is on the list for my next series of models. The primary focus so far is to build something which will stand rough handling.
By comparison, my A/B T-Bird weighs in at 24 .oz with a K & B Greenless Head .23 for power. The OS .19 for A class is an ounce lighter.
Back when I was building A-1 Nordic Gliders ( I still prefer the old class designations), I was hard pressed to get one under 6 .oz. The minimum weight then was 5.08 .oz.
l’m a little suprised how light your Dragmaster is—is it strong enough?
Guess it’s okay for open sailplane, but needs weighting up to about 14 and a half ounces for F1A/A2.
Gos, you are right the Dragmaster it is too light for F1A, I built the model to fly in classic glider, which does not have a minimum weight requirement. You are also right about the strength, no zoom launches due to wing flutter and hope it does not nose in on landing. It may be a little to fragile for serious competition but is fun to fly.
EdEd,
The 5.5 oz Mulvihill seems a little on the heavy side. Take some off it and put it on the Dragmaster!
Hope to see you at the Nats!
BillHey Bill, good suggestion, I never thought of that one. Maybe I could take thr hook off the Dragmaster and put it on the Mulvihill and fly it in classic glider. Seriously I think I could build a new wing and recover the fuse on the mulvihill and save some weight. I am looking forward to the NATS as well, we still have our pop-up camper, but the RV show is in Knoxville this week and Jane may twist my arm to buy a travel trailer. I sure like camping at the field. See you there.
EdThe Maverick is right in there. There are lighter ones, but durability is an issue. The ‘Duster at 7 oz is lighter than mine. That’s a LOT of plane for a TD. The Dragmaster is definetly under the legal weight.
If the Mulvihill doesn’t fly as well as you’d like
wellllllllllll you could always do as the r/c guys do….. put a bigger motor on it.Anyone with P-30 experience that could share how the weight is apportioned; wing stab and fus./prop/. I know the max rubber motor wt. is 10 g, and min wt of model, without motor is 40 g. I’d like to try a birdcage”
wing, and wonder what I’d be aiming for, for the structure/covering wts.
Cheers; TIA,d-ddeezildon,
these are the weights of my P30’s
Pezazz: Tail Firster
prop 8.9 9.5
stab 4.3 4.1
fuse 14.2 12.2
wing 17.8 15.0
total= 45.2 40.8hope this helps
EdIt may surprise you but most overweight is from too much glue. f you use one oz of superglue during construction, the whole oz is still there forever.
Here are a couple of tips. When using glue like titebond, spread a small amount on a scrap of plastic, like a coffee can lid. When installing ribs, just touch the end of the rib in the glue puddle and install it. No excess will develope. When using CA, squirt a puddle in a plastic film can lid, then use a short length (6-8in) piece of either 1/32 or 1/16 piano wire to dip in the glue puddle and transfer a drop to the work. With this, you don’t saturate the wood with un-needed glue. When using epoxy, the most important glue is between the two pieces being glued. The epoxy squeezed out is just baggage.
In my opinion, weight is not much of a factor except on indoor models.
The important thing is to build the model WELL enough so that it will stand up and hold the trim.
I think even my old 1/2 A Spacers with a light engine and tissue covered were over 6 ounces with a Tatone tick off timer.
My heavy duty modified 1/2A T-Bird, “MaxBird” weights over 8 ounces and always flys well if I point it in the right direction!
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