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Old Jun 27, 2008, 06:01 AM
Canadian Bacon
flypaper 2's Avatar
Kingston, Canada
Joined Jun 2004
12,662 Posts
I put a 9 in. spar in the upper wing too, at the back of the centre struts. There is a weakness at the end of the fuel tank. On the first one I made, I put flying and landing wires made from dental floss, very strong stuff.

Gord.
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Old Jun 30, 2008, 09:43 PM
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teamgs's Avatar
Elk Grove, CA
Joined Mar 2004
476 Posts
I completed my brushless moth a few weeks ago, but due to wind and other time issues, I have only flown her twice. Very nice flyer, with the exception of sloppy and large aileron rolls. I have since moved the control rods to the outer holes of the servo horn, and will see if that helps any.

She weighs in at 20.5 oz. including at around 2 oz of paint, pilot, upgraded wheels and reinforced landing gear, and 5.5 oz 1700 MAH lipo.

Here is a link to my short build/maiden thread.

http://www.rcgroups.com/forums/showthread.php?t=882860

All in all, an EXCELLENT relaxing flyer.

Regards,

Gary
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Old Jul 01, 2008, 01:21 AM
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azdavidr's Avatar
Phoenix, AZ
Joined May 2008
83 Posts
thanks

Quote:
Originally Posted by rperego
Dave - here are pics showing the attachment points for my cross brace "wires". The tabs are made from bits of flexible plastic. For the inner lowers on the wing, there is a backing plate for screwing into that I imbedded in the foam and spackled over. As you can see from my not very tidy attachment of the Kevlar, keeping the thread tight while making a knot isn't easy.

I just saw a new TM build the other day where the fellow put a CF rod in the bottom of the upper wing, the same length as the lower one (had to notch the cabanes). He did this because with his first TM he snapped the upper wing just outboard of the cabanes. All I can figure is with the flex that the stock struts have, in say an aggressive outside loop, the struts flex instead of transferring the load to the bottom wing. He did not reinforce the struts (other posts) or use the E-flightline plywood ones.

Same fellow also installed upper ailerons - huge difference in roll rates.
Bob,

Thanks for the GREAT tip on the drill set. Perfect, and what a great price trade-off. Thanks for the pics too. My fuselage is done as are the rudder & elevator. I've put in a thin CF tube in the upper wing ... hoping that's enough. I'm to the point where I've done a trial fit of the electronics. Servos & RX are working, so I'm off to finish up the wings & cowl. After that I'm ready to maiden.

thanks again for the tips!

Dave
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Old Jul 06, 2008, 02:57 PM
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Elk Grove, CA
Joined Mar 2004
476 Posts
battery question

The puffed Hextronik 1700 MAH lipo I have been using seemed to be running out too quickly. I used my wattmeter, and found that it was only giving around 1100 MAH performance. I am thinking about replacing it, but have a question regarding balancing.

Using my high tech "fing-o-meter" balancing device, it appears that my plane balances right at the front of the upper rear cabanes. This is supposed to be the perfect spot. I had thought of going with a 1200 lipo, saving a couple of ounces, but then I guess I will have to add lead, as my battery bay is already hogged out as far foward as possible. Unless I wish to allow the battery to go into the cowl.

My AUW right now is 20.5 oz.

Do you think it is worth trying to open up the battery bay some more, and get a lighter battery, or just stick with a 1500-1700 MAH?

Regards,

Gary
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Old Jul 06, 2008, 03:09 PM
Rock Climbing and RC >:)
Andrew32's Avatar
Colorado Springs, CO
Joined Nov 2005
290 Posts
Thought I aught to post a pic of my completed Tiger Moth 400.

The only thing that I needed to do was make sure the CG is correct, lately I carved out most of the front cockpit to put the battery further forward.

P.S. It also has a GWS Brushless, well worth putting in.
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Old Jul 06, 2008, 03:19 PM
Dance the skies...
Tom Frank's Avatar
United States, MA, Walpole
Joined Dec 2003
17,441 Posts
Quote:
Originally Posted by teamgs
The puffed Hextronik 1700 MAH lipo I have been using seemed to be runung out too quickly. I used my wattmeter, and found that it was only giving around 1100 MAH performance. I am thinking about replacing it, but have a question regarding balancing.

Using my high tech "fing-o-meter" balancing device, it appears that my plane balances right at the front of the upper rear cabanes. This is supposed to be the perfect spot. I had thought of going with a 1200 lipo, saving a couple of ounces, but then I guess I will have to add lead, as my battery bay is already hogged out as far foward as possible. Unless I wish to allow the battery to go into the cowl.

My AUW right now is 20.5 oz.

Do you think it is worth trying to open up the battery bay some more, and get a lighter battery, or just stick with a 1500-1700 MAH?

Regards,

Gary
I'm flying mine with packs as small as 15C 1200 mAH 3S (Fusion brand... lighter weight than most). My packs slide forward against a foam "crash cushion" stop about 1/2 in. aft of the front surface of the firewall. I could move the pack further forward, but the plane still flies fine there with a bit of down trim.

I should also mention my CG is closer to the back edge of the rear cabane struts with the lighter pack, but the TM seems to be very tolerant of the CG placement. When swtiching packs from the 1200 to my larger 1350 ones, I slide to the same forward position, and just adjust for level flight at mid throttle with the trim button on my TX after take off. Handling after that feels pretty much the same as with the lighter pack.
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Last edited by Tom Frank; Jul 06, 2008 at 03:25 PM.
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Old Jul 06, 2008, 03:50 PM
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Quote:
Originally Posted by teamgs
Using my high tech "fing-o-meter" balancing device, it appears that my plane balances right at the front of the upper rear cabanes. This is supposed to be the perfect spot.
Here's a cut and paste from one of Tom Frank's posts in which he explains how to set the center of gravity on the Tiger Moth 400. I saved it in my archives...

"The easiest way to balance the TM400 is to support it in the upright position with your fingers on the underside of the upper wing on the inner cabane rails where they glue into the upper wing. Does this make sense? If your fingers tips are on these rails as far aft as you can get them (when the bump into the rear inner edge of the vertical cabane strut), you will be supporting the plane where it should balance."
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Old Jul 06, 2008, 04:15 PM
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teamgs's Avatar
Elk Grove, CA
Joined Mar 2004
476 Posts
Beautiful plane, Andrew. You are going to love its flight characteristics.

The balance point with my 5.3 oz. 1700 is right at the front bend of the rear part of the upper cabanes. If I pull back my battery around 1/2 to 2/4" then the balance point moves to the rear most point of the upper cabanes. I think I can get away with a slightly smaller battery and have no issues.

BTW, after adjusting the aileron control rods to the outermost holes in the servo arm, the rolls are significantly better, though still pretty slow. Not sure if I want to add the second set of ailerons or not. I will have to fly her some more.

Regards,

Gary
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Old Jul 06, 2008, 05:58 PM
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Joined Jul 2007
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I put an EVO 1345mah in mine. It balances at Tom Frank's sweet spot with the battery about 3/8" to 1/2" back from the firewall. It could come back even more if I didn't have a 9gm spinner and a bigger ESC than necessary. My ESC is right up against the firewall. The EVO is nice (although expensive) because it is short but not so wide or thick that I had to carve out much foam.
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Old Jul 07, 2008, 12:34 PM
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Elk Grove, CA
Joined Mar 2004
476 Posts
I just ordered a couple of 1200's. They are shorter by about an inch than my 1700, and 1.5 oz lighter. This should allow me to push the battery's COG further forward, to compensate for the lighter weight.

BTW, while landing in the ball diamond infield the yesterday, I hit a soft spot, and dumped the plane on its nose. I learned how to take apart a bell motor. That was the only way to remove the dirt from inside the windings/stators.

My reinforced landing gear held very well, though.

I noticed as the wind picked up, that the TM400 got tossed around much more than did my EasyStar, and was much more of a handful to fly. I guess it is the draggy airframe, and possibly that my ES is a little heavier with the 8 cell packs. The EasyStar was fun to try and slow to zero groundspeed.

Gary
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Old Jul 07, 2008, 12:39 PM
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Quote:
Originally Posted by teamgs
I noticed as the wind picked up, that the TM400 got tossed around much more than did my EasyStar, and was much more of a handful to fly. I guess it is the draggy airframe, and possibly that my ES is a little heavier with the 8 cell packs. The EasyStar was fun to try and slow to zero groundspeed.

Gary
Hi Gary,

You hit the nail on the head! The EasyStar is aerodynamically much more efficient than the TM 400. In fact, a stock EasyStar, with a 7 cell NiMh only puts out about 10 ounces of thrust!

Weight, hasn't anything to do with wind fighting ability though. Which is why a little 11 ounce GWS Formosa will handle wind like it's almost dead calm.

Chuck
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Old Jul 07, 2008, 12:46 PM
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Elk Grove, CA
Joined Mar 2004
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The formosa is good for wind, eh? After building my boomer, I will have to look at that one. Sigh...I am already running out of space in my garage for all the models.

Gary
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Old Jul 07, 2008, 01:19 PM
Canadian Bacon
flypaper 2's Avatar
Kingston, Canada
Joined Jun 2004
12,662 Posts
The shorter wingspan on the bipes makes them a little more bouncy in the wind too. Also why they're more agile.

Gord.
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Old Jul 09, 2008, 12:13 PM
Another 3DHS convert...
Newnan GA
Joined Mar 2006
726 Posts
Alright guys, I need a cheap and decent ESC/motor (brushless) combination for my TM. Has anyone tried these motor/esc combination buys from Hobbycity? And if not, what would you guys recommend? I have 5 3S lipos so I should be good there. I'm just worried that they may be too heavy for this bird. I have two 1800mah batteries from xcitebattery.com that are very light and should do the job. Just basically any words of advice would be helpful.
Thanks.

Link to Hobbycity Combos
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Old Jul 09, 2008, 12:23 PM
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Quote:
Originally Posted by jetboy11914
Alright guys, I need a cheap and decent ESC/motor (brushless) combination for my TM. Has anyone tried these motor/esc combination buys from Hobbycity? And if not, what would you guys recommend? I have 5 3S lipos so I should be good there. I'm just worried that they may be too heavy for this bird. I have two 1800mah batteries from xcitebattery.com that are very light and should do the job. Just basically any words of advice would be helpful.
Hi jetboy,

I haven't tried any of those combos from HobbyCity, so can't speak with any authority or experience relative to their worthiness. With that said however, it's my opinion that the TM 400, if built light, seems to work very well with a motor in the 900-1000 kV range, and somewhere around 10 amps constant current rating.

An example would be the Hobby Lobby EssKay 400XT at 960 kV, or the E-Flite Park 400 920 kV. Both of these motors are 10 amp motors, and with a 3s Li-Po, will run very nicely, with authority on an 'APC 8x6E Thin Electric', or a 'GWS 9x5 DD Direct Drive' prop.

For an ESC, I would recommend something in the range of 50% higher than the current draw of your motor. I personally use an 18 amp ESC, for example.

Just my opinion...

Chuck
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