HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Dec 02, 2007, 05:23 PM
AMA 14680
Foamenator's Avatar
Northern Nevada
Joined Mar 2007
1,581 Posts
Discussion
Blu-Sail II and the Joy of Monobloc and KFm Wings

Some time ago Tony 65x 55 posted plans for several of his designs using "monobloc" construction and "KFm wings". The common trait of these plans using "monobloc" and "KFm's" is they are easy to build, in-expensive, practically indestructible and to me most importantly designs that are easy adaptable to materials on hand, and last but not least are realistic flyers. Since Tony made his work available to us, I have built three Blubabies, one SE5A, one Pawnee PA36 and most recently the Blusail glider which I converted to a motor-glider. I thought I would post info and pics of this build here in a new thread, as it was introduced over in Tony's Pawnee thread:

http://www.rcgroups.com/forums/showt...748508&page=48 post 713 and has gotten buried over there. My maiden report on the first build is posted later in that thread.

This design is literally a one day build. On my third flight, I broke the fuselage in three pieces attempting a high-speed loop. This is the second fuse, structurally more sound and 1.5 oz lighter including paint. I haven't maidened it yet (no rush since we are being pumbled with high winds for the next few days) so I decided to throw a little paint on it. As you see it here, the parts are just sitting and not glued together yet. As usual, I welcome any comments or feedback. Bob

UPDATE: Here are Tony's Blu-Sail Plans copied over from the Pawnee Thread. I should have done this in the beginning. Bob
Foamenator is offline Find More Posts by Foamenator
Last edited by Foamenator; Sep 02, 2008 at 10:08 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Dec 02, 2007, 08:44 PM
Postcards From The Purple Edge
tuppertn's Avatar
United States, OK, Sand Springs
Joined May 2007
3,919 Posts
Quote:
Originally Posted by Foamenator
I will just use tape to save weight....
That looks like more than just tape, Bob. Knew you couldn't resist.

Looks awesome. I'm anxious to hear how it flies. Is this one Rediboard as well?

kendall
tuppertn is offline Find More Posts by tuppertn
Reply With Quote
Old Dec 02, 2007, 08:55 PM
AMA 14680
Foamenator's Avatar
Northern Nevada
Joined Mar 2007
1,581 Posts
Quote:
Originally Posted by tuppertn
That looks like more than just tape, Bob. Knew you couldn't resist.

Looks awesome. I'm anxious to hear how it flies. Is this one Rediboard as well?

kendall
LOL... Darn that Wally World 49 cent paint anyway. After wasting 1/2 roll of black trying to get a smooth finish on the wing, I decided a shark was lurking inside. I used the original wing and tail and spliced the fuse sides out of rediboard to get the length. The top and bottom pieces are 9mm EPP. I extended the monobloc back to behind the rear wing tiedown, since this is where it broke last time. The monobloc is lamininated with EPP and 1/2 inch Elmers. The other one flew great and this one is slightly lighter (even with the paint) so I think it will be fine. As soon as the winds die down, I'll let you know.
Foamenator is offline Find More Posts by Foamenator
Reply With Quote
Old Dec 02, 2007, 10:08 PM
I'm not flying backwards!
Tony65x55's Avatar
Oshawa, Canada
Joined Sep 2004
3,753 Posts
Gawd, I love your builds. I'm dying to hear about the maiden.

Tony
Tony65x55 is offline Find More Posts by Tony65x55
Reply With Quote
Old Dec 02, 2007, 10:19 PM
You deserve my opinion
FirstShirt's Avatar
Collierville, TN
Joined Apr 2005
1,497 Posts
Bob, I have to agree with Tony. You are "The Man." That's a real beauty. Looking forward to following your progress. Pat
FirstShirt is offline Find More Posts by FirstShirt
Reply With Quote
Old Jan 02, 2008, 03:21 PM
Registered User
United States, MI, Parma
Joined Aug 2006
200 Posts
Foamenator

It was very interesting to find there was a weak spot in the fuselage. Good stuff to know when building.

I was interested what the CG location was that you used, didn't see it in the plans?

Looks like the wing is three piece. Did you use any CF tube in the center section for added strength?

With your motorized version what is your AUW running?

I plan on making one of these out of FFF. Hopefully I can get started on it this week. Probably won't get a chance to fly before spring though. Good flying days in Michigan are rare this time of year.

Did you set the tail up with an angle gauge of some sort or did you just measure it and adjust it so it looked OK?

Thanks for any input you have.
Rolland Benson is offline Find More Posts by Rolland Benson
Reply With Quote
Old Jan 02, 2008, 04:51 PM
AMA 14680
Foamenator's Avatar
Northern Nevada
Joined Mar 2007
1,581 Posts
Rolland.... Thanks for taking a look at the Blu-Sail thread. She is a sweet flying bird for sure even if she is a little speedy. Our winds here are terrible this time of year, so I've never been able to get her up high and let her soar. All of her flights (7) have been around 200 feet with limited use of power to keep her in tight for landings. Let me answer your questions one by one....

Ques.... It was very interesting to find there was a weak spot in the fuselage.

Ans.... The weak fuse was mostly the result of using Readiboard. I don't think you will have any stength problems. I would reinforce the foam with strips of nylon strapping tape on the inside of the fuse at any rate.

I was interested what the CG location was that you used, didn't see it in the plans? CG is abou between 3 and 3.5 inches aft of the leading edge depending on the battery I'm using. I've pretty much settled on a 11.1 volt 350 ma Kokam which balances out about 3.25 in aft of the leading edge.

Ques...Looks like the wing is three piece. Did you use any CF tube in the center section for added strength?

Ans...The wing is 3 piece. There is no main spar. with the 3 layers of foam overlapping, this area is plenty strong so far. I did add bamboo spars across the outer wing panel joints for strength.

Ques...With your motorized version what is your AUW running? AUW is 17.1 oz with the Kokam battery.

Ans... Did you set the tail up with an angle gauge of some sort or did you just measure it and adjust it so it looked OK? I leveled the fuse then used two rulers to make sure the stab was mounted properly

Hope this help.... Be sure to let me know if there is anything else I can do. Bob
Foamenator is offline Find More Posts by Foamenator
Reply With Quote
Old Jan 02, 2008, 06:20 PM
I'm not flying backwards!
Tony65x55's Avatar
Oshawa, Canada
Joined Sep 2004
3,753 Posts
Rolland, there's a little v-tail trick to getting the alignment. As shown on the plans, the correct distance between the tips of the v-tail is 16". Simply tape a piece of string to the tips, 16" long and then eyeball it for straightness with the wing on. You can get it very precise using this method as you are creating a triangle, the only geometric shape which cannot be changed without creating a change in the length of its sides. As for pitch alignment, the Blu-Sail's v-tail sits in two small FFF blocks that align it for pitch. Try it, it works.

Tony
Tony65x55 is offline Find More Posts by Tony65x55
Reply With Quote
Old Jan 02, 2008, 07:16 PM
Registered User
United States, MI, Parma
Joined Aug 2006
200 Posts
Bob & Tony

Thanks for the input. I'll get started and check back in again once I get it flying, most likely when the weather breaks in the spring.

Thanks Again
Rolland Benson is offline Find More Posts by Rolland Benson
Reply With Quote
Old Jan 03, 2008, 08:43 AM
Registered User
United States, MI, Parma
Joined Aug 2006
200 Posts
Bob

What are you using to glue up the KFm3 wing panels. I was thinking of either UHU or a spray foam adhesive I have used before. Seems like the spray would be the easiest and cheapest way to go.

Thanks
Rolland Benson is offline Find More Posts by Rolland Benson
Reply With Quote
Old Jan 03, 2008, 09:49 AM
I'm not flying backwards!
Tony65x55's Avatar
Oshawa, Canada
Joined Sep 2004
3,753 Posts
Rolland, I use the spray foam for laminating and the UHU type for joints where the adhesion surface is smaller. PU for high stress areas. Epoxy for quick repairs.

Tony
Tony65x55 is offline Find More Posts by Tony65x55
Reply With Quote
Old Jan 03, 2008, 07:34 PM
Registered User
United States, MI, Parma
Joined Aug 2006
200 Posts
Did you guys use afibre tape on the bottom of the wing. Got mine together and it seems like it has alot of flex to it.

Also are you setting the stab on top of the fuselage? Didn't see any incidence in the plans, but Tony has two blocks to align it. Are these for strength or to set the stab incidence?

Thanks
Rolland Benson is offline Find More Posts by Rolland Benson
Reply With Quote
Old Jan 03, 2008, 07:40 PM
AMA 14680
Foamenator's Avatar
Northern Nevada
Joined Mar 2007
1,581 Posts
Quote:
Originally Posted by Rolland Benson
Did you guys use afibre tape on the bottom of the wing. Got mine together and it seems like it has alot of flex to it.

Also are you setting the stab on top of the fuselage? Didn't see any incidence in the plans, but Tony has two blocks to align it. Are these for strength or to set the stab incidence?

Thanks
Rolland I did put 1" nylon strapping tape on mine on the inside. Keeping it out side top and bottom will work fine as well. I also used the strapping tape to join the wing leading edges.

I mounted my tail section by beveling the area of the fuse where the tail mated with the fuse to match the stab angle and expoxyed it in place one I got it aligned. It seems to be plenty strong. Bob
Foamenator is offline Find More Posts by Foamenator
Reply With Quote
Old Jan 03, 2008, 08:05 PM
Registered User
United States, MI, Parma
Joined Aug 2006
200 Posts
Bob

One other thing I just thought of was tapering the trailing edge of the wing. Is it tapered on the top or bottom side. In other words if it was sanded which side is it sanded on? All of my previous KF wings I never tapered anything.

Thank You
Rolland Benson is offline Find More Posts by Rolland Benson
Reply With Quote
Old Jan 03, 2008, 08:29 PM
AMA 14680
Foamenator's Avatar
Northern Nevada
Joined Mar 2007
1,581 Posts
Quote:
Originally Posted by Rolland Benson
Bob

One other thing I just thought of was tapering the trailing edge of the wing. Is it tapered on the top or bottom side. In other words if it was sanded which side is it sanded on? All of my previous KF wings I never tapered anything.

Thank You
Rolland... Only the two leading edge pieces are beveled 45 degress where they are joined. Once the piece is folded over onto the main wing section and glued down the leading edge will appear rounded. I hold these two pieces together with nylon straping tape. Bob
Foamenator is offline Find More Posts by Foamenator
Reply With Quote
Reply


Thread Tools