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  • November 15, 2019, 05:23:06 AM

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Author Topic: Profile from full fuselage plan  (Read 676 times)

Offline Craig Beswick

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Profile from full fuselage plan
« on: October 09, 2019, 03:14:59 AM »
Hi guys,
can you tell me if I can copy a side view from a full fuselage plan and build a profile fuselage from it? I guess the answer is sure go right ahead, but.....

I suppose the question is, will it still fly as it should or are there aerodynamic issues that need to be addressed first?

I am a novice and don't think my Super Clown is going to last very long! I have an Accentor which, once I am competent, I will build but I think I need a lot more practice yet and a profile seems to make a lot more sense.

I would rather not buy another profile kit, I think I am competent enough to build what I need, I am just not up to the technicalities of design.
Regards
Craig

Offline 944_Jim

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Re: Profile from full fuselage plan
« Reply #1 on: October 09, 2019, 06:25:54 AM »
Mr. Craig,

Just do it! Some may say a profile fuselage flexes more than a full fuselage, but other than that you have no addditional concerns.
I would also recommend you build the wing minus the ribs that the full fuselage fits on, in other words remove the center section. You may wind up moving a bellcrank platform to the bay just left of center or leave it centered in the wing, but sheet the middle bay to give the profile fuselage something to hang onto.
I would build the wing with a center rib and sheeting straddling the bay to either side of the center rib. This is so the fuselage leverages a structural piece through the wing (the rib), and something for you to stick your covering to when you have to repair the model (the sheeting).
Jump over to Outerzone to review (too many possible) profile models to see how profile fuselage models in your size "wear their wings."
And over on Flyinglines.org there is a document on Flying Clown Racing. It describes a few hints regarding profile Clowns in a two-part paper.
Lastly, show the build log, please.

Offline Ken Culbertson

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Re: Profile from full fuselage plan
« Reply #2 on: October 09, 2019, 08:17:28 AM »
Hi Craig

Not sure what your goals are but if they are stunt then you are going the right direction. Nothing at all wrong with profiles.  When I was starting out I did exactly what you are doing with a Nobler.  Finished learning the pattern on that profile. For now, don't worry too much about flex and twist.  They are only issues when you get well past beginner and and someone is judging the quality of your maneuvers.  It is difficult to learn how to do consistent maneuvers with your tail flopping around but not to simply learn them.   Make the fuselage strong at the wing joints and use stiff ( but not too heavy) wood for the stab you will be fine. 

When you get the hang of it there are several ways to build a profile fuselage that has minimal flex and twist that you can find in threads here.  When the time comes to start flying PA you should probably transition to full body.  Flying a profile there is like going to the Governor's ball in blue jeans and a T-Shirt.  Doesn't matter how good you dance.

Good Luck! - Ken
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Offline Motorman

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Re: Profile from full fuselage plan
« Reply #3 on: October 09, 2019, 10:06:12 AM »
The Tanager is the exact same airplane as the Accentor except the Tanager has a profile fuselage so yes, you can do it with no problems. Do not leave out any ribs but the push rod should come out on the inboard side so your controls don't clog up with castor oil.


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Offline Ty Marcucci

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Re: Profile from full fuselage plan
« Reply #4 on: October 09, 2019, 10:40:37 AM »
I have done this when teaching my land lady's grandson how to fly.  He wrecked the Brave, so I made a profile fuselage. Only problem was the slab of 1/2 inch balsa was too light. Use firm straight grain balsa in the 7 to 9 pound area. Stiff and not that heavy with the wing cut out in the fuselage. Less twist in maneuvers as well.

As stated, be sure to have the push rod come out on the inside and have the bell crank moved to the inside for push rod clearance as well.  Only takes about 2 inches for this. I highly recommend using medium hard balsa on the inside of the fuselage as vibration damper.  A 1/2inch thick slab that goes  from the nose to the high part of the wing. Shape it so it flows into the fuselage.  Also it is not necessary to shape the fuselage by carving and sand it it to a "round" appearance, just round off the sharp edges. H^^
Ty Marcucci

Offline Randy Powell

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Re: Profile from full fuselage plan
« Reply #5 on: October 09, 2019, 10:54:54 AM »
You could also build up a profile fuselage. Use some internal structure to minimize the tendency of profile fuselages to twist from torque.
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Offline john e. holliday

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Re: Profile from full fuselage plan
« Reply #6 on: October 09, 2019, 11:13:08 AM »
Many designs of full fuselage planes have been done.  Several ways to make a profile fuselage stiff, but for mee the easiest is to laminate 1/4 iche sheets with Gorilla Glue, the amber stuff.   Use lots of clamps and be advised the stuff does expand.  It will fine every worm hole in the balsa as well as oozing out the edges.  I have done that on several profiles because the 1/2 inch was too soft. D>K
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Offline Ken Culbertson

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Re: Profile from full fuselage plan
« Reply #7 on: October 09, 2019, 12:33:57 PM »
As stated, be sure to have the push rod come out on the inside and have the bell crank moved to the inside for push rod clearance as well....
There is another reason to do this if your plane has flaps.  All of the driving force will be on the inboard flap.  The outboard will be driven by the inboard.  If there is any twisting in the flap horn you will get a slight roll when the flaps are used.  At least this way the roll will be to the outside, not the inside.

Ken
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Offline Craig Beswick

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Re: Profile from full fuselage plan
« Reply #8 on: October 09, 2019, 01:55:55 PM »
Thank you all so much for the responses, very encouraging!

In no particular order. I have been thinking about a built up fuselage because decent wood at a reasonable price is hard to come by here and shipping from the US is price prohibitive. But I think it somewhat defeats the time saving I am looking for.

I do like the laminating idea of the 1/4" Doc that is probably the way I will go, also probably the quickest and easiest.

Thanks for the advice Ty and the tip about sanding the profiles. I completely rounded off the Super Clown and it doesn't look right!

Thank you Ken for the technical advice and wood selection tips, off to get that wood thus morning.

Thank you one and all, I really appreciate the feed back.
Craig

Offline Tim Wescott

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Re: Profile from full fuselage plan
« Reply #9 on: October 09, 2019, 04:14:27 PM »
If you're really picky, move the propeller shaft down about 1/4 inch or so from the full-fuse version.  Assuming that the original had the vertical CG centered on the wing, that'll tend to keep it there.
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Offline Craig Beswick

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Re: Profile from full fuselage plan
« Reply #10 on: October 09, 2019, 06:22:21 PM »
Hey Tim,
I planned to leave the thrust line where it is just move the engine bearers to accomodate it. "Beam On", I think it is called.

Currently the CG is 60mm behind the LE. I will be changing the wing shape/rib sizes to be like a Twister, same size from fuselage to tip.

From what I have read that will change the CG. I have the NASA calculator for working out CG so, hopefully, that will be okay.
Craig

Offline Tim Wescott

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Re: Profile from full fuselage plan
« Reply #11 on: October 09, 2019, 06:42:23 PM »
Hey Tim,
I planned to leave the thrust line where it is just move the engine bearers to accomodate it. "Beam On", I think it is called.

Currently the CG is 60mm behind the LE. I will be changing the wing shape/rib sizes to be like a Twister, same size from fuselage to tip.

From what I have read that will change the CG. I have the NASA calculator for working out CG so, hopefully, that will be okay.
Craig

I was only suggesting the move if you're really picky.  And I was talking about the vertical location of the CG -- not fore and aft, which is what you're thinking.

Don't trust a calculator for the CG of a full-scale aircraft -- control line stunt planes want their CG's way farther forward than would be considered reasonable for RC or full scale.  I'm not sure if there's a good calculator for CL stunt, but if you're copying the entire Twister layout, copy its fore-aft CG location as well.
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The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Craig Beswick

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Re: Profile from full fuselage plan
« Reply #12 on: October 10, 2019, 02:37:20 AM »
Hello Tim,
clearly I still have an enormous amount to learn!

I did not realise there was a vertical CG. I have a full fuselage Accentor kit and it has the wing shape I was looking for and is the size I wanted so it seems an easy fit to use it as a template for the profile. I assume the horizontal CG will stay the same?

I cut the ribs today and they are the best I have done, so happy about that. Sanded with 220 grit, should I go to 400? I was only able to get 7lb to 9lb balsa for them. Should I remove some more wood from the TE end to help with weight?

Many thanks
Craig

Offline Ken Culbertson

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Re: Profile from full fuselage plan
« Reply #13 on: October 10, 2019, 08:24:13 AM »
I cut the ribs today and they are the best I have done, so happy about that. Sanded with 220 grit, should I go to 400? I was only able to get 7lb to 9lb balsa for them. Should I remove some more wood from the TE end to help with weight?
I would remove some from the inboard wing especially as you get close to the tips.  If you are using adjustable leadouts (please!) you need to make sure that the leadout wires clear all of the ribs by at least 1/4" in both the most forward and most aft positions.  This may wipe out the center section of the last couple of ribs near the tip which is ok.  If you are putting on cap strips (your ribs look like a sheeted LE with cap strip design) you can trim to about 3/8 from the top and bottom, 1/4 if your ribs are stout.  Once upon a time I only removed from the inboard wing thinking I was replacing tip weight with strength.  Not a good idea.  Make it as light as you can on both sides.  If you have tip blocks you can not hollow the outboard one if you want.

Ken
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If it is broke, replace it.
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Offline afml

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Re: Profile from full fuselage plan
« Reply #14 on: October 10, 2019, 08:36:21 AM »
"The Tanager is the exact same airplane as the Accentor except the Tanager has a profile fuselage so yes, you can do it with no problems."
Also from Brodak is a full bodied Oriental AND the profile Oriental.
A check on the plans will reveal any differences.
One option is to purchase the fully bodied version and copy the ribs or buy a laser cut rib kit.
Build the kit as a profile, when 'finished', take the remaining kit and extra ribs and finish with a full fuselage version.
Good luck & "Tight Lines!" H^^
Wes
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Offline Craig Beswick

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Re: Profile from full fuselage plan
« Reply #15 on: October 12, 2019, 12:43:43 AM »
Hi all,
Ken, I lightened up the ribs some more. They went from 22 grams to 21, so a win! Yes I will be putting in adjustable lead outs and a weight box. I'm still deciding about tip blocks, I'm not the best at carving.

Hey Wes, great suggestion, thank you. My problem is I live in the Antipides, Australia. I tried to buy an Oriental kit from Leester, he was unbelievable helpful! I think the best shipping price we got was $260US!!!!!!!! Because the box was over 4 feet.

Having said that Brodaks has the cheapest shipping to Australia. I generally try to put a bulk order in to make it worth while.
Thanks for the help
Craig

Offline Craig Beswick

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Re: Profile from full fuselage plan
« Reply #16 on: October 12, 2019, 12:53:55 AM »
Guys could I ask for suggestions on an engine for this model?
The plans say 35 to 46.

I have at my disposal, an OS35fp, OS 40fp, OS46fp and an Evolution 36.

I would like to use the Evolutionnot for any particular reason, but, if there is a good reason not to then I won't.

52" wing span
37.5" long
571 sq in wing area
Thanks
Craig

Offline john e. holliday

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Re: Profile from full fuselage plan
« Reply #17 on: October 12, 2019, 10:22:42 AM »
All those would be great.  I think the Evolution is the heavy weight though.   D>K
John E. "DOC" Holliday
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AMA 23530  Have fun as I have and I am still breaking a record.

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