Tailless F5D Limited? Multibumm! - Page 11 - RC Groups
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Dec 01, 2008, 07:58 PM
The Kid
Thekid3418's Avatar
Yeah yeah yeah!

Are the mubu 2 airfoils any different? If you could post them it wouldn't hurt.

Troy, do you have any pictures of this "beach bum"?
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Dec 02, 2008, 12:35 AM
One Idiot is plenty...
Dbox's Avatar
Quote:
Originally Posted by biber
If anybody is interested in the actual Mubu II airfoils, I will post them, or I'll put them on webspace (doesn't need to much of that) and link it.

biber
Biber ,please do.
I used MH 44 thinned 8% and 1% camber.I find info in one of Your posts.
Enlarged Your drawings of Mibu II on scanner to 1260mm and it was all data about the plane.I changed cores twice and still dont like a transition between
in the middle of the wing,looks and feels not right.
Not sleeping good,thinking what to do with it
Yuri.
Dec 02, 2008, 05:12 AM
Registered User
I used M120 and M160 Foils from MubuII. Good Transition. They are here (RCGroups) somewhere. Tested MubuII without motor, not much sucess... I think my fins are too small and my launch is too dirty

Here they are:
https://www.rcgroups.com/forums/show...36&postcount=3
Last edited by _King_Pin_; Dec 02, 2008 at 05:25 AM.
Dec 02, 2008, 05:31 AM
Needs brain lubrication
biber's Avatar
I've upped the airfoils so they are downloadable:
m120
m160

The m120 is the inboard panel's airfoil, the m160 the outboard one.
Transition is at the span station with the step in the TE.
At that step the inboard panel has 120 mm chord and the outboard one has 160 mm.
The airfoil set is designed, so that about the forward 50 mm are basically identical.
The wingskin does run straight along and the spar doesn't have a step, nor does the d-box part of the wing.
That means m120 has 9.6% max thickness at 37% chord and 1.2% camber at 49% chord.
M160 is 7.2% max thickness at 29% chord and 0.9% camber at 35% chord.

The Mubu II will work with the Multibumm foils aswell, but the m1X0 are made to fit it better from the construction point of view.
Luckily those mods make sense from an aerodynamical standpoint, aswell.
It's funny how things are interweaved in the Mubu II and how harmonically it all plays together.
That's one big improvement over the Multibumm which was somewhat crude in this regard.

Edit:
Thanks King Pin, I didn't remember that it was posted somewhere here, already.
Anyway, it's available.

We made the experience that surprisingly small fins suffice as long as the CG is right.
The CG location is crucial, anyway.
We had launches failing with the old Multibumm sometimes, but not so with the Mubu II so far.
My Mubu II will have a pulling prop, however, to enable power on launches.
I hope to launch it by myself then, with tranny in the left.
Now as it's a pusher launches require a helper to be save.

biber
Last edited by biber; Dec 02, 2008 at 05:52 AM.
Dec 02, 2008, 11:22 AM
One Idiot is plenty...
Dbox's Avatar
Thank You guys.Now You are talking,after I wasted half sheet of 250 dense foam Have to get more foam ,I guess.
Yuri.
Dec 02, 2008, 12:58 PM
Registered User
Quote:
Originally Posted by biber
Now as it's a pusher launches require a helper to be save.

biber
Humm... I don't have a helper!
I'll change it to pulling prop config probably... So that I can launch motor on?
Dec 02, 2008, 06:37 PM
Needs to do 52 legs !!
jjmouris's Avatar
Mmmm, motor in the nose seems good!

Looking foward to pictures of the new fuselage.

Joe
Dec 04, 2008, 08:40 PM
One Idiot is plenty...
Dbox's Avatar
With airfoils corrected,Wings came out at 7oz or 200 gr.Sheeted with 1/64 ply .
Sorta light,but feels heavy to me.Good part ,wings are strong and almost no flex.Did not cut nose curve and tips yet.Planning to join them inside fuse.
Yuri.
Dec 04, 2008, 10:13 PM
Caution:Makes sharp left turns
Troy's Avatar
Quote:
Originally Posted by Thekid3418
Yeah yeah yeah!

Are the mubu 2 airfoils any different? If you could post them it wouldn't hurt.

Troy, do you have any pictures of this "beach bum"?
https://www.rcgroups.com/forums/show...1&postcount=91
https://www.rcgroups.com/forums/show...&postcount=119
https://www.rcgroups.com/forums/show...&postcount=124
Dec 04, 2008, 10:20 PM
The Kid
Thekid3418's Avatar
Hey yuri, how stiff is stiff? I ask because I have a relative forest load of 1/64 ply (two 5x5 ft sheets), and not much 1/32 balsa or 1/16 balsa which is what i was planning on using. Its hard to get good balsa around my house, i have to drive about 20 miles to get to a hobby shop...

If you say 1/64th is good its what i'll use to sheet the wing, otherwise I think i'll be going with 1/32nd on bottom and 1/16 on top, which if memory serves is just thick enough to bury standard micro servos (HS-81s) in and have them be flush...
Dec 04, 2008, 10:33 PM
Caution:Makes sharp left turns
Troy's Avatar
Yuri, any carbon hiding under there?

Biber, how much anhedral did you use on the Mubu II? Same as Mubu I?

On a good note, I just got my vacuum pump back today. Now to find some blue or pink foam and some mylar.
Dec 04, 2008, 11:00 PM
Cumulus Altimus
FASTBEN's Avatar
yuri looks great i knew you find a way to go.....now the rest.
ben
Dec 04, 2008, 11:49 PM
One Idiot is plenty...
Dbox's Avatar
Wing is STIFF VERY MUCH even torsionally.This 1/64 is little heavy for my taste
but ,boy,glued together from top and buttom with Gorilla glue,it rock solid.
Troy,I was trying to fit some unidirectional carbon stripes in there but decided,not to ,on proto at least.not for economy sake for saving on weight.
I did put a balsa spar and now I am gluing in bass wood LE and curves.
I was also planning glassing wing with at least 3/4oz glass.It would make it even stiffer,but still thinking to save on weight and just cover wing with ultracote or some...Trailing edge is strong enough as well without carbon.
In terms of servos,all You can fit flush, is on the picture
Dec 05, 2008, 05:33 AM
Needs brain lubrication
biber's Avatar
Quote:
Originally Posted by Troy
Biber, how much anhedral did you use on the Mubu II? Same as Mubu I?
Yep.
-3 degrees each side, like on the Multibumm.

Yuri, Paul and I fitted D60 to the Multibumm and aswell to the Mubu II.
Granted, you have to grind the bodies to get another half mm and need a thin wingskin.
Then you get them flush to the surface and cover them with a sticker.
Paul and I might try to get them readily installed including RDS before closing the molds on one of the next models.
Would be too cool.

biber
Dec 05, 2008, 09:00 AM
Carbon fiber is our friend
Steve C's Avatar
Troy,
Some of the Home Depots have pink. I have to drive an hour to get it, but at least it's around here.

Steve C


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