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Old Jul 04, 2005, 11:58 PM
Crash Master
Gene Bond's Avatar
Indianapolis, IN
Joined Sep 2001
16,632 Posts
Build Log
Blu-51cd A/E/T Simple Fun Fighter

Here's one that's been back-burnered for a while...

30"ws
200sqin
7.3oz RTF
15t/24g GBv motor
8040HD prop
2s830
5.25oz/sqin
~100W/lb

It's just a simple 3 channel A/E/T plane. The wing is flat, with a 4/40TLAR airfoil. The wing is braced with a single heavy skewer hot-glued into a slot. The H-fuse crutches are hot-glued in place. The motor is held in with 2 small skewers hot-glued to the fuse intersecting diagonal corners with some 2-sided tape wrapped around the bearing tube, and some tie-wraps holding it to the skewers.

It's a fun one! Took right off from the first launch, and I had Jerbear video it during the first pack. We got a little, sorry for the light. Later I was trying to hover it, and wondering why the rudder wasn't working I went for the 4/40 underchamber to eliminate CG/pitch issues and also promote a reasonable glide. It worked! It flies fine inverted, too, as seen in the video. Roll rate is reasonable, maybe 3/sec... Loops are easy, inside or outside. Turns are not bad at all.

Slap one together and have a blast! Or go racing I was going to do it up in 'Miss America' Colors, but chickened out & went military.

It's built very similarly to my C-47, so no surprises.

Honestly, I was hoping it'd come out about an ounce lighter, but I didn't do anything special, either. It could be built an easy ounce lighter with 3mm Depron, but the wing would need reinforcement. Maybe a hybrid???

One note: I had to use a 90° servo arm instead of 180°, so the ailerons would work right. The angle that they are from the servo means that there would not have been adequate up travel, and excessive down. This would have given bad adverse yaw. See the pictures.

I'm sure there are plenty of other power systems that'd work. They wouldn't be as powerful and light, but a couple of ounces backed by a few more watts (and some bracing) aught to be OK.

Maiden Video

Edit, Warning: It seems most of us are coming out tail heavy when building per the plan... This means the battery is being mounted in front of the cg in order to balance. It is a better practice to try to balance the plane without the pack, but with all the other equipment. To do this, mount the motor and use some tape to temporarily hold the servos and other equipment in place, trying to get it to balance on the cg. This way, using different weight packs will not affect the cg. GPW suggested moving the wing back 1" from the plan, This is good advice, based on the input thus far. I have not revised the plan, but you probably should consider the change in your build.

Edit: New Plans uploaded 4-17-06, with the wing moved back. Just make sure the peak of the wing is about the start of the canopy. You can check the balance before cutting the wing slot by taping the components in place without the wing in place.

Step-by-Step built thread: http://www.rcgroups.com/forums/showthread.php?t=577951

Added a scaled up print to 48", and added the ips size (24")...

Suggest trying a KFm airfoil for better wind pennetration, bu I haven't tried..

Decrease the dihedral for a sportier flight.

Decrease the wing incidence for higher speed w/o climbing.
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Last edited by Gene Bond; Jan 21, 2009 at 09:11 PM. Reason: New Plans
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Old Jul 05, 2005, 06:07 AM
gpw
“There’s no place like Foam”
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United States, LA, New Orleans
Joined Jul 2002
24,109 Posts
Gene, Thats SUPER!!!!! Everyone around here has been waiting and wanting a good P-51... This is it!!!!! ...got the plans , making temps .... Thanks again !!!!!
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Old Jul 05, 2005, 07:34 AM
Crash Master
Gene Bond's Avatar
Indianapolis, IN
Joined Sep 2001
16,632 Posts
We all know the formula that works TOG taught us! It's the 30", 200sqin planform that's proven so versatile for J-250 power, and now is even better for CDR power... More power, less weight, how could that be better?

I know Jerbear has made 20-30 different configurations of A/E/T planes, trying to come up with the perfect sport plane. All have been close in size and some variations in shape and wing position, but we keep coming back to similar areas.

My concern was to make something that rolls axially, yet still turns good, just on ailrerons. This one seems to fit the bill. It doesn't get stupid untill way down in the post-stall realm, where the rudder is the only real attention-getter on any plane.

Oh yea, throws:
ailerons: 1.25" up, 1" down (less would be good to start with)
elevator: 1" each way

I need to try it out on a pylon course, now... It flew so well with the 8040HD prop, I forgot to try the 7x6 APC I took along! It should pick up the speed a good bit, but the low speed thrust would suffer.
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Old Jul 06, 2005, 06:25 AM
Crash Master
Gene Bond's Avatar
Indianapolis, IN
Joined Sep 2001
16,632 Posts
Maybe there's too many P-51's out there? Hope to get some feedback, Glen. Jer's building one now. Looked pretty good last night when I stopped by.

Next up may be a little bigger one. I may want to try a larger, heavier Mustang... maybe for 400 power on 3s packs. I'm thinking 40-48" ws, and a fully flat-bottomed wing with built up fuselage. The one that's had my eye for a while is the Thunder Tiger Lazy P-51... but for $120 for a balsa ARF, it's too much investment for the way I fly Maybe 2 sqft, 1 lb, and 100 watts? We'll see! Need to play with the scale a little. Retracts would be cool, but wouldn't last on the grass runway at the club field...

I may want to revise these plans a little, sliding the wing back a tad. It was a little tough to get the nose weight where it needed to be with this light CDR motor. That's the kind of feedback I need.
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Old Jul 06, 2005, 07:03 AM
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st99's Avatar
United States, PA, Greene
Joined Jan 2005
313 Posts
Hi Gene,
I like your P-51 design. Will try one a litle later, when I get some time.
I will be building quite a few this Winter.

A 40 inch wing span would be the one that would fit my needs right now.
Just bought a bundle of Blue Fan Fold at Low's.
Thanks for the interesting posts.

BW
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Old Jul 06, 2005, 04:00 PM
Crash Master
Gene Bond's Avatar
Indianapolis, IN
Joined Sep 2001
16,632 Posts
I hope to start on the 40" design real soon. I'm buncing ideas around in my head One of the good ones will pop out soon.
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Old Jul 06, 2005, 06:09 PM
Suspended Account
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kentucky
Joined Dec 2003
577 Posts
Slow down, Mr. Bond...I haven't even maidened my copy of your DC 3 yet!
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Old Jul 06, 2005, 06:49 PM
Crash Master
Gene Bond's Avatar
Indianapolis, IN
Joined Sep 2001
16,632 Posts
Quote:
Originally Posted by badaltitude
Slow down, Mr. Bond...I haven't even maidened my copy of your DC 3 yet!
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Old Jul 06, 2005, 08:39 PM
Registered User
kentucky
Joined Feb 2004
624 Posts
this looks a good everyday flier but i'm still enjoying the other (4f) 51. I made another fat fuse/wing similar to the 4f-51 but with a longer fuse and stab/elevator. tried it today and it worked great.

Bob
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Old Jul 06, 2005, 09:03 PM
Crash Master
Gene Bond's Avatar
Indianapolis, IN
Joined Sep 2001
16,632 Posts
Sounds good, Bob... Post a picture over in that thread... I thought about that, for a little more stability. It may entice me
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Old Jul 06, 2005, 11:30 PM
On patrol.
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Broomfield, Colorado
Joined Jun 2004
1,287 Posts
Right now, I'm trying to decide on my next project: Larger wing (Nutz, WW, etc.), 35-40" full fuse bipe, Park Jet, and a scratch design/build full fuse cut cores P-38 are all on my list. Your 40" full fuse, real airfoil P-51 might fit the bill also.

I will probably go with cut cores and fiberglass. I go back and forth between the quick building profiles to "get it in the air" and the fiberglassed semi-scales to satisfy my need for some craftsmanship.

BTW: Was flying the C-47 last night at dusk in a stiff breeze. Love that C-47; I'm still smiling. Waiting on some new motors and props to fine tune my "El Cheapo" racer but it looks promising.
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Old Jul 07, 2005, 06:22 AM
gpw
“There’s no place like Foam”
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United States, LA, New Orleans
Joined Jul 2002
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Well , between cowering in the closet and picking UP fallen trees , limbs, etc. managed to get a P-51 built... No pics yet , too busy with storm damage ...soon ... Hope to fly it this weekend ..C ya'...
Oops ,another storm on the way .... time for that vacation UP North ....
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Old Jul 07, 2005, 07:00 AM
Crash Master
Gene Bond's Avatar
Indianapolis, IN
Joined Sep 2001
16,632 Posts
Get all that weather out of the system before next weekend! It'd be a shame to have to sit in a bar the whole time!

The drawings are coming right along on the 'Slow-Stang-400'.

I'm very pleased with performance of this one. The inverted flight is something I was hoping would be acceptable, and is at least that. It cracks me up that an underchambered wing can fly this well. Slow, Fast, Inverted, and whipping the corners like a pylon racer... all with one little skewer for a spar Not enough can be said for building light.

Not sure if it'd be anywhere as good with the extra ounce or so of a geared 250 or 300, but should be fine with a 20-24" carbon fiber tube imbedded in thw wing. Then again, if fast is more of a concern than light and lively, try it! I'd go for a low ratio, like an A or 1s, with the correspondingly smaller prop. It may even be a decent ship on a J-250 DD with a 4x2.5 or one of the Hobbico Props.
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Old Jul 07, 2005, 07:36 AM
gpw
“There’s no place like Foam”
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United States, LA, New Orleans
Joined Jul 2002
24,109 Posts
Worse case scenario.... sitting in a shelter , no power , cold food , no computer ... and 86 degrees and muggy ....Dennis on the way !!! If it hits here , ya' might as well go to Montana ... Things are a mess around town now, lots of trees down , trash everywhere.... heck of a little storm went through ... I've got to remove some big 70' oak trees that were blown over in the yard .... same all over town ... we're just hoping that Dennis doesn't visit so soon .... we may have to evacuate , and that's another epic tale ...

on the bright side , I did have time for building .... by candlelight , and the hot glue gun didn't work ....hahahahahaa
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Old Jul 07, 2005, 12:59 PM
Registered User
Dallas Texas
Joined Oct 2004
917 Posts
Gene, I would love to see some plans for 400 powered warbirds of any type. I have built quite a few of the smaller profiles and powered them with 350s, but I usually use 8 cell Nimh, and the motors don't last long at that voltage. I have started experimenting with geared 400s and they don't seem to have as good power to weight as the 350s but they don't burn up as quickly either. It's about time for me to try me hand at something with a full fuselage and wing, and your plans have always been easy for me to build from so I look forward to seeing what you come up with. Do you intend to use some of the fold-over technique I saw on your pattern plan design from a few months ago? That looked like a great build. As always, thanks for your help and inspiration.
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