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Feb 27, 2006, 10:58 AM
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P. Tritle's Avatar
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Build Log

35" Dehavilland DH-4 for IPS and 3 ch.


I really do like 4 bay Biplanes, and Biplanes flown by "our side" in WW-I are a bit scarce, so the DH-4 is perfect in both arenas. The drawings are pretty well roughed in now, and construction has begun.

The model has a 35" span and 305 sq, in. wing area. Power will be a 3.5: 1 IPS system with a 2 cell 700 Lipo. Prop clearance is definately an issue if scale landing gear is used, so it looks like it'll need a 7" prop, hense, the lower gear ratrio. We'll see how it works. Guidence will be 3 ch. R/C with a target weight around 8 - 8 1/2 oz.

PAT
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Feb 27, 2006, 11:03 AM
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P. Tritle's Avatar
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Framing the Tail Section


The bowed outlines for the rudder and elevator were done first using 2 laminations of 1/16 X 1/8 balsa. The rest of the frame up is all standard stuff using 1/8 sq. and 1/16 X 1/8 balsa. The hinges were cut in 1/8 wide strips from light Cya hinge stock.
Feb 27, 2006, 11:10 AM
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P. Tritle's Avatar
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Framing the Wings


Both wings are of equal span and chord, but the center sections and strut attachments are different. The basic structure incorperates the laser cut main spars with 1/16 sq. rib bottoms and laser cut rib tops.

The strut attachment hard points are incorperated into the ribs and main spars on the top wing, and the ribs and spanwise stringers on the bottom. The cabanes will glue into small pockets in the center section ribs. The wings will be rigged, so minimal strength is required in the outer panel / center section is required -- which means it's going to be light. Should be a very scale like flyer!

PAT
Feb 27, 2006, 08:16 PM
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Gerry Markgraf's Avatar
Pat
When you start on of these build articles, it usually means there is a new kit in our future. I hope so cause the DH-4 is an important airpane in US WW I history as well as after the war. It also was an important part of our civil aircraft beginnings as it served long and well as a mailplane. The Army, Marines and Navy all used them so there are lots of options. I'm sounding knowledgable cause I found ny old Profile #97 on the DH-4. Your build article dosn't state what version you are building. I'll be hoping for a DH-4B although I don't guess its too much effort to convert from one version to the next.
Gerry
Feb 27, 2006, 08:58 PM
Veni Vidi Volavi
Brian Allen's Avatar
Pat

You are killing me !!!! I can not figure out how you can keep hurning these great designs out like clockwork. Does Charlie cut parts for anyone but you!!!????

Is this going to be a Dumas kit or one of yours?

Do you ever sleep?

Brian Allen

Veni Vidi Volavi

I came I saw I flew
Feb 27, 2006, 09:23 PM
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P. Tritle's Avatar
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Thanks Guys!!! This one is intended for Dumas. It's the first of 3 WWI erea biplanes. The others are -- wweeelllll, maybe you'll just have to wait and see
The original plans were drawn from a small 3 view GA drawing pulled from the Rand McNally Encyclopedia of Millitary Aircraft. Other more detailed reference came from the Wylam drawings in Scale Aircraft Drawings Vol. I. The model is definitely a sport scale offering, so it's a bunch easier to get the general layout from a less detailed starting point.
The planned color scheme is the blue and yellow U. S. Navy bird.
PAT
Feb 28, 2006, 12:52 PM
Registered User
I'll defer any thoughts I might of had of converting a Guillows DH-4 in favor of this. And a Dumas line of 30 inch+ span WWI crates is most intriguing. RE-8? Be-2c? Albatross CIII? Salmson?
Last edited by PhilA; Feb 28, 2006 at 02:37 PM.
Mar 01, 2006, 12:04 AM
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portablevcb's Avatar
Guys, you gotta understand that Pat does NOT sleep! He just cranks out drawings at night and builds by day. And, if you want other WWI planes I'd be happy to cut them for Pat As well as anything else he designs.

You can also bet that if he builds it the thing will fly like a bird! About every other plane he flies he declares his new favorite. Then he builds another one and that one flies even better

The problem is the Dumas stuff takes a long time to get to kit (but, they really do it right). The rest of the stuff goes to magazines. In either case we get to wait for almost a year before we get to build them! Just to make you all jealous, I get to watch them fly all the time

charlie
Mar 08, 2006, 09:18 AM
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Framing the Fuselage


Now that the T-Craft is finished, attention will be turned toward finishing this one. And after the T-Craft, C-150 and the Pacer, this one seemed like a no-brainer!

The side frames were built over the plans and joined via formers and cross pieces. The chin is stringered back to the front landing gear mount, and the tailskid mount plate is glued in between the aft longerons.
Mar 08, 2006, 09:22 AM
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Framing Continues


The motor mount was built up using the laser cut gussets to set up the right and down thrust. The remaining top side stringers were added next, using 1/16 X 1/8 balsa forward, and 1/16 sq. aft of the rear cockpit.
Mar 08, 2006, 09:28 AM
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Adding the Cockpit Fairings


With all the wood work done, the forward and rear cockpit fairing patterns were made from typing paper. Those patterns were then transfered to yellow file folder to make the actual parts. The paper fairings were "curved" into the rounded shape by carefully pulling them around a, Xacto knife handle. The stringers were cut out of the forward cockpit, and the fairings glued in place with Pacer Canopy glue.

Next step is to get the servos and control system in place.

PAT
Mar 08, 2006, 10:05 AM
T A C

Subscribed


Hey Pat ....

Looks like another beauty !

Rus
Mar 08, 2006, 11:37 AM
Registered User
Whoo Hoo!
Looks great. My Grandfather helped uncrate these in France in 1918. Also helped stack them for the famous billion dollar bonfire. He didn't like that part much.

I can't wait to see it kitted.
sp
Mar 08, 2006, 01:05 PM
Summit Model Aeronautics
Steve85's Avatar
Pat,

Looks great. My only recent WWI is a Guillow's SE5a, and I've been hankering for something a little bigger. The DH4 looks like a winner, and being a scratch-builder myself, I've been meaning to treat myself to a kit sometime soon. Imagine, a carefully-designed, laser-cut kit that someone else (like Pat Tritle!) has figured out how to convert to electric power! Pinch me someone, I'm dreaming...any idea when Dumas might offer it as a kit?

Steve
Mar 08, 2006, 01:09 PM
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vintage1's Avatar
Missed this one pat. I can confirm that 7x6 works well on the 3.5:1 gears on 2s LIPO.

If it lacks go, get an A geared unit (5.86:1?), same prop and 3s LIPO. That gives +50% power for no extra heating.

Watch out for BEC issues on 3s LIPO tho.


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