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Oct 21, 2019, 06:50 AM
Father by day, hacker by night
JornWildt's Avatar
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Originally Posted by hadihf
Thanks....just curious ..are there any 'factory drawings' for tiger moths being used for reconstruction?
I remember looking for that kind of drawings for another aircraft - and found a couple of references stating that they would explicitly *not* provide such things to avoid being sued later on by builders that failed to construct an airworthy aircraft (or, perhaps, rather their family).
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Oct 23, 2019, 02:11 PM
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Need a little expert opinion.

Estimated RTF weight is 1100 gms (39oz). With a total wing area of 670 in. sq., the loading comes to around 0.06 oz/in. sq. Planning to install EMax GT 2820-07 with 3S 2800 Mah Lipos. Is it OK or overkill?

Will be flying slow like scale.
Oct 25, 2019, 01:39 PM
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Bottom wings almost done. This assembly weighs 88 gms.
Oct 26, 2019, 12:37 PM
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Quote:
Originally Posted by hadihf
Need a little expert opinion.

Estimated RTF weight is 1100 gms (39oz). With a total wing area of 670 in. sq., the loading comes to around 0.06 oz/in. sq. Planning to install EMax GT 2820-07 with 3S 2800 Mah Lipos. Is it OK or overkill?

Will be flying slow like scale.
Hadihf,

As usual, your builds are elegant with details such as the sprung landing gear as well as the pull-pull controls on the elevator and rudder.

The Tiger Moth is a scale favorite model in Canada as thousands were built here (as well as Australia) during WWII as well as a big pilot training program using the TM. The Canadian Tiger Moth had the designation 82C and has some differences from the British version, such as a full canopy and a heating takeoff from the exhaust due to harsher winters here.

Not an expert but the most interesting thing about your projected specs are the light wing loading. I translate the projected weight and wing area into a simple wing loading of 8.5 ounces per square foot and a cubic wing loading of 3.9 (to get cubic wing loading divide the simple wing loading by the square root of the wing area expressed in square feet). The Ampeer newsletter has a flight performance chart for the cubic rating: 3 to 5 is described as "backyard", above indoor (0-3), and below parkflyer (5-7) and sport and some trainers (7-10).

I ran some scenarios thru the Ecalc, an electric flight performance predictor, using both the Emax GT2820-07 (850kv), weighing 4.9oz and the Emax GT2218-09 (1100 kv), weighing 2.8oz, a 30 amp esc and asp electric 12x5 and 11x6 props. Both setups work fine - Ecalc gives the stall speed 15mph for both engines - the wing loading change for the lighter motor is minimal, 8.5 to 7.9 simple wing loading and 3.9 to 3.7 cubic. No temperature alarms with either prop on either motor..

The larger motor on the 12x5 gives a projected thrust of 47.6 oz , prop pitch speed of 35mph, 234watts in/199watts out (the motor has a max. watt rating of 656), efficiency of 86% and a load on the battery of 8.6 C (staying under 15C allows use of lower C lipos). 103 watts per lb, a thrust weight ratio of 1.22:1 and flight times of 6.1 minutes and 11.1(mixed throttled) , 40degrees C

The smaller. but higher kv motor (max watts 312) on the same prop also generates 47.6 oz thrust, a prop speed of 36mph but at lower efficiency of 69%, higher temperature of 72degrees C, lower flight times of 4.8minutes and 8.7, 132watts per lb, 1.23:1 thrust/weight ratio, still without triggering any alarms and a battery load of 10.7C (but I wouldn't go beyond a 12/5 and 11/6 props on this motor).

Let me know if you would like me to run any other prop/motor combination.

btw, just to be super scale, the Tiger Moth, in addition to the two top stub ribs in each rib bay, between the leading edge and the front spar, also has one bottom stub rib in each rib bay, centered between the two top stub ribs. (smiley)

best wishes

Michael in Ontario, Canada
Last edited by 2michaely; Oct 26, 2019 at 01:29 PM.
Oct 27, 2019, 07:47 AM
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Quote:
Originally Posted by 2michaely
Hadihf,

btw, just to be super scale, the Tiger Moth, in addition to the two top stub ribs in each rib bay, between the leading edge and the front spar, also has one bottom stub rib in each rib bay, centered between the two top stub ribs. (smiley)

best wishes

Michael in Ontario, Canada
Thanks Michael for such a detailed analysis. Will use GT2820/07 as have one already. Need to reverse the shaft to fit in. Also will add the leading edge lower stub ribs.

Best Regards
Farooq
Last edited by hadihf; Oct 28, 2019 at 07:00 AM.
Nov 02, 2019, 02:02 PM
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Lower Wings Covered. This assembly weighs 135 grams minus servos.
Nov 10, 2019, 11:56 AM
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Top wings done w/o covering. Weighs 120 gms. TM is not complete without corrugated tank. Need to figure how to do that.
Nov 19, 2019, 09:04 PM
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rblubaugh's Avatar

rblubaugh


I have just learned about this build thread and will be anxiously waiting your next step, the corrugated tank. I like electric planes.

Bob
Nov 20, 2019, 09:10 AM
Father by day, hacker by night
JornWildt's Avatar
I knew I had seen that somewhere, but couldn't remember where :-) Cool idea Blink.
Nov 20, 2019, 09:13 AM
Father by day, hacker by night
JornWildt's Avatar
And here is Longhorne's way of doing it: https://www.rcgroups.com/forums/show...5#post41839995
Nov 21, 2019, 04:04 AM
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Guys, Thanks for sharing such great ideas. Very helpful.
Nov 25, 2019, 12:23 PM
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Following Colonel Blinks technique, found 1mm diameter nylon string good to go. So here is the result. Will post pics of painted tank soon.
Nov 25, 2019, 12:34 PM
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rblubaugh's Avatar
That really looks good. The painted tank should look even better.

Bob
Nov 25, 2019, 01:58 PM
So I'M meant to be in control?
Colonel Blink's Avatar
Looks a darn sight better than mine did!!!!


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