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DHC-4 question

#1
Best greetings to all. I'm new to the community, and I'm hoping that someone can give me a bit of advice. I'm working up plans for a DHC-4, about 62" span, mostly 'cause I want to play with flaps. In looking at images of the plane, I'm trying to figure out the best way of attaching the nacelles to the wing. I'd like to have it rounded to make it easier deal with the inboard flaps. I'd appreciate any help anyone could offer.
 

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Merv

Well-known member
#2
Welcome to the forums.
It hard to visualize exactly what you have in mind. A picture of your build would be helpful. I use hot glue and strapping tape to hold my motors in place.

It’s great that you want to design your own plane. I’d recommend building a few of the FT planes first. If you run into trouble, we will be able to give far more assistance if we are dealing with a known plane.
 
#3
Best greetings to all. I'm new to the community, and I'm hoping that someone can give me a bit of advice. I'm working up plans for a DHC-4, about 62" span, mostly 'cause I want to play with flaps. In looking at images of the plane, I'm trying to figure out the best way of attaching the nacelles to the wing. I'd like to have it rounded to make it easier deal with the inboard flaps. I'd appreciate any help anyone could offer.
Thanks, Merv. I appreciate the input. Is there a preferred format for images? I'll post what I have so far.
 

Merv

Well-known member
#4
Thanks, Merv. I appreciate the input. Is there a preferred format for images? I'll post what I have so far.
No, not that I’m aware of. The way you did the wire diagram was fine. Most videos are uploaded to YouTube, then copy and paste the the link on the forums.
 
#5
Hope this attachment works. I'm working on the wing at this point, generally a Clark Y as indicated. My gut says inboard height of the spars is too small despite what the airfoil says. And of course, the nacelles with attached inboard flap is an architectural issue. I have not yet cut foam -- I like doing it on CorelDraw first, then assemble it is Blender to check 3d fit(s). THEN I get to cut foam!
 

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Bavarian_RC

Well-known member
#8
Welcome to the community. Looks like a nice project! Your plans are already on a good track. Maybe you want to have a look at the build thread of my Heinkel 219. There are some pictures showing my design of the nacelles. There are no released plans yet as I am still flight testing, but I think I will be ready in a few weeks. If you have questions on some specific elements of my solution, let me know.
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#9
Bavarian, you are a life-saver. You're way ahead of me, particularly with nacelles. Version 0.2 of mine are already in progress after putting the first page on foam! I appreciate the wisdom, thanks.
 

Bavarian_RC

Well-known member
#10
Glad if I could help you. In the meantime my plans and the build instruction are progressing quite well. I hope to have them out soon. Could give you a better inside view of my design. I keep following you, keep updating your progress.
 
#11
Well, I did call it an alpha version, and here's a good example of why. The canopy roof is very much the wrong size, and the side pieces need rework to make them fit properly. Going back and forth between software packages doesn't help much, either, but I will keep at it. I can start seeing what it will look like when done, which is the motivation I need. Here's a pic from Blender for your amusement.
Caribou Oops.png
 
#12
An Update on the Caribou

I have cut foam for my version of the DHC-4 and put MOST of the parts where they belong. Please see the photos, below, to examine the wreckage. I do have a couple of notes before the next step, which is to take everything apart and measure, measure, measure. Then re-draw the plans and give things another try:
1. Mental gymnastics are much harder after age 60 than before. The nose just doesn't go together properly. I just can't get the picture in my head to come out flattened on the paper. I think I may try the panel layout lines on the 3-view as the starting place for the next version.
2. I'm sorry, but the squared off idea for nacelles and fuselage doesn't do it for me. I have to redesign for cylindrical nacelles and to soften the line of the top of the fuselage. It will also help to have everything the appropriate length from the start.
3. Vertical stabilizer/horizontal stabilizer construction -- good points: the use of a "wrapper" for the vertical stabilizer to lock in the horizontal stabilizer at mid-height worked, although I do have to get the horizontal stabilizer cut-outs done correctly. More mental gymnastics, I guess. The doubled horizontal stabilizer is, well, an issue. It puts a lot of additional weight at the worst moment imaginable, and cutting the hinge is an issue. I like the idea of a central hinge of doubled paper but I think there may be other methods of achieving this end. Same with wings. I think I need to redesign with undercambered wing and single thickness horizontal stabilizer.
4. Wing tips -- see photos below. This worked nicely and seems to offer a way of replacement as necessary due to violent trees and the ever inimical ground.
I will update with the new measurements and design as I get it completed. The final picture illustrates my response to design frustration. All I have to do now is wait for my yard to dry enough to maiden the Commuter. It will be painted bright yellow with military markings in honor of the 152 owned by a good friend, who calls it "Tweetie." He just bought a 170 for better travel, but I still like that little plane.

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#15
Grumbling to all! I am continuing to work on the Caribou, sort of. I cut the overall size by a quarter to avoid some of my ongoing issue with build weight. Seems I build planes like I build everything else: solid! While working on the 'Bou, I built a Communter and just because I like the way it looks, tried a DH-2. Both came in with high weights and CG issues, the Commuter because of the builder and the DH-2 on design. Weight moments just got away from me (see attached). I think it DH-2 needs a boom of skewers or something to keep weight under control. Maybe when I get the 'Bou done I'll try to rework it. I do love the look, and a glider version did well.
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Oh, and the Commuter wound up with a bit of an aft CG with unsurprising results. I'm getting very good at pieces!
 
#17
Thanks, Merv. Now if they would just fly properly, I'll be ecstatic! For the DH-2, I used a C-pack for the power to try to counteract the weight. Cut down a prop to make it fit. Seemed to do well, but promptly nosed in from a couple of feet. Peeled the bottom back, battery and electronics survived, so I think I need to build something else.

Something light.