Ultra Sport 40 Kit Bash
03-03-2009, 06:36 PM
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Ultra Sport 40 Kit Bash
Started this a couple weeks ago and thought I should share.
I'm building an Ultrasport 40 that I've bashed to have Forward Swept Wings. This is a concept that's intruged me since I was a kid and I've always wanted to build one so here goes. I've gone with 8 degrees forward sweep and i've also modified the tail and enlargened the rear fuselage. I moved the engine about 2" forward to compensate for the change in CG and mounted it inverted.
So far so good.
I'm building an Ultrasport 40 that I've bashed to have Forward Swept Wings. This is a concept that's intruged me since I was a kid and I've always wanted to build one so here goes. I've gone with 8 degrees forward sweep and i've also modified the tail and enlargened the rear fuselage. I moved the engine about 2" forward to compensate for the change in CG and mounted it inverted.
So far so good.
03-04-2009, 04:58 PM
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RE: Ultra Sport 40 Kit Bash
More work today - finished the pushrod installation and have glued on the bottom sheeting.
Crate - The dihedral was left alone. I figure with the increased tail moment and surface area I should be okay. It's a pretty stable platform as is so I should be okay.
Crate - The dihedral was left alone. I figure with the increased tail moment and surface area I should be okay. It's a pretty stable platform as is so I should be okay.
03-04-2009, 05:27 PM
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RE: Ultra Sport 40 Kit Bash
are you gonna use the sullivan tail wheel?
if so to what are you gonna mount it?
im stuck one step ahead of you right now with US 60 but i want to do the same LG like you planned.
you are changing the wing........
the wing is the best feature of the US so they say, why are you changing it?
if so to what are you gonna mount it?
im stuck one step ahead of you right now with US 60 but i want to do the same LG like you planned.
you are changing the wing........
the wing is the best feature of the US so they say, why are you changing it?
03-04-2009, 06:07 PM
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RE: Ultra Sport 40 Kit Bash
I'm not sure on the tail wheel yet actually, just had one of those in Cad. I'll probably either use a bushing type that has a hinge type piece to mount in the fuse and the rod goes in the rudder - simple and effective. If I use a sullivan type I'll replace that piece of 3/32" balsa with a piece of ply and mount it to that.
As far as the wing goes all I've changed is the sweep angle. I moved the outer most rib ahead 3.5" to create a forward sweep of 8 degrees. I based the wing planform off a German WWII design ([link=http://www.luft46.com/heinkel/hep1076.html]He P.1076[/link]). As far as why goes, well I already have an US 40 & US 60 so I thought why not take a really good design and tweek it rather than building one from the ground up.
As far as the wing goes all I've changed is the sweep angle. I moved the outer most rib ahead 3.5" to create a forward sweep of 8 degrees. I based the wing planform off a German WWII design ([link=http://www.luft46.com/heinkel/hep1076.html]He P.1076[/link]). As far as why goes, well I already have an US 40 & US 60 so I thought why not take a really good design and tweek it rather than building one from the ground up.
03-04-2009, 09:42 PM
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RE: Ultra Sport 40 Kit Bash
Shouldn't be any different from any other aircraft. About 33% MAC.
Because of the sweep it's moved forward about an 1-1/4". Will then tweak it with flight tests.
Because of the sweep it's moved forward about an 1-1/4". Will then tweak it with flight tests.
03-06-2009, 09:03 AM
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RE: Ultra Sport 40 Kit Bash
In case you're interested in forward swept wings. I've been doing some digging...
I found two sets of plans for forward swept RC airplanes.
FSW-3
and
Sweepee.
You can buy both short kits from Ed down at lazerworks.
And the plans are still available too.
If I remember correctly, both are 40 sized birds.
Just in case...
Oh.. another thing... You may want to consider fully sheeting your wings. I remember an article that one plane designer was test flying his rc bird, and during a pass he saw the wings start rolling up and ripped right off.. Forward swept wings need to be very, very strong.. or you need onboard computers...
I found two sets of plans for forward swept RC airplanes.
FSW-3
and
Sweepee.
You can buy both short kits from Ed down at lazerworks.
And the plans are still available too.
If I remember correctly, both are 40 sized birds.
Just in case...
Oh.. another thing... You may want to consider fully sheeting your wings. I remember an article that one plane designer was test flying his rc bird, and during a pass he saw the wings start rolling up and ripped right off.. Forward swept wings need to be very, very strong.. or you need onboard computers...
03-07-2009, 10:39 AM
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RE: Ultra Sport 40 Kit Bash
Finished off the rear of the fuse.
Finished adding the torque rods and sanding them to shape.
Sanded center section of wing now getting ready to fiberglass.
I'm going to try and use epoxy instead of CA. I've never done it this way before but it should leave a nicer/stringer joint and finish.
Finished adding the torque rods and sanding them to shape.
Sanded center section of wing now getting ready to fiberglass.
I'm going to try and use epoxy instead of CA. I've never done it this way before but it should leave a nicer/stringer joint and finish.
03-07-2009, 03:08 PM
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RE: Ultra Sport 40 Kit Bash
Well, I think it went pretty well. Very happy I used gloves though. That would have been messy. Will see how it turns out after it dries.
Tried using some of the methods suggested [link=http://www.airfieldmodels.com/information_source/how_to_articles_for_model_builders/construction/joining_wing_panels/04.htm]here[/link] but I couldn't seem to tack it with the CA very well, so I just cut that bit off and carried on.
Was pretty cold out in the shop (just above freezing) so moved it onto the sundeck where it's about 45 degrees to dry.
Tried using some of the methods suggested [link=http://www.airfieldmodels.com/information_source/how_to_articles_for_model_builders/construction/joining_wing_panels/04.htm]here[/link] but I couldn't seem to tack it with the CA very well, so I just cut that bit off and carried on.
Was pretty cold out in the shop (just above freezing) so moved it onto the sundeck where it's about 45 degrees to dry.
03-07-2009, 08:49 PM
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RE: Ultra Sport 40 Kit Bash
An issue has arisen.
There are what look like air bubbles trapped along the length of the glass. Where it is wrapped will not stay down.
Any ideas?
There are what look like air bubbles trapped along the length of the glass. Where it is wrapped will not stay down.
Any ideas?
03-08-2009, 01:14 AM
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RE: Ultra Sport 40 Kit Bash
I had tried to while it was wet. I think I inadvertently stretched the cloth too much.
When its fully hardened should I cut those sections out and lay new cloth over the affected areas or just sand it down and leave it?
When its fully hardened should I cut those sections out and lay new cloth over the affected areas or just sand it down and leave it?
03-08-2009, 11:19 AM
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RE: Ultra Sport 40 Kit Bash
Totally right about it not being a huge issue. When first laying it down (for you NEXT project plane) Wet the area with an initial spattering of Epoxy then start from front or back and slowly lay the cloth down working the air out from under the cloth as you go. If it gets under you can squeegee it out without having to work to much of cloth around....This is the BEST use of a credit card, especially in these times we have today!!!!!!
The build is looking GREAT!!!! It's getting warmer outside as the days keep marching towards Summer!!!!! Get it ready to fly........
The build is looking GREAT!!!! It's getting warmer outside as the days keep marching towards Summer!!!!! Get it ready to fly........
03-08-2009, 02:48 PM
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RE: Ultra Sport 40 Kit Bash
Alright - So I forgot the bubbles and just carried on.
Sanded the glass down and seems to be okay. In retrospect I think I didn't use enough epoxy. This was some very heavy cloth and along with stretching it too much that's what I ended up with.
It may be getting warmer in Florida but not up here. The winter just seems to keep on going. It keeps teasing us. Right now it's -14 (celcius) with the wind chill but nice and sunny. It's supposed to warm up by next weekend but I'm not holding my breath.
Sanded the glass down and seems to be okay. In retrospect I think I didn't use enough epoxy. This was some very heavy cloth and along with stretching it too much that's what I ended up with.
It may be getting warmer in Florida but not up here. The winter just seems to keep on going. It keeps teasing us. Right now it's -14 (celcius) with the wind chill but nice and sunny. It's supposed to warm up by next weekend but I'm not holding my breath.
03-08-2009, 05:46 PM
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RE: Ultra Sport 40 Kit Bash
Well, Murphy struck again.....
Got the wing all lined up and set to go. Then one of the wing dowels got stuck and I couldn't get it out without destroying it. Ugh....
The pictures show the amount I had to remove and the repair.
I'm happy with how the repair worked out but it was a lot of work that was really unneccessary, especially since I thought to myself while doing it "boy, I hope this comes back out".
Oh well. good now.
Got the wing all lined up and set to go. Then one of the wing dowels got stuck and I couldn't get it out without destroying it. Ugh....
The pictures show the amount I had to remove and the repair.
I'm happy with how the repair worked out but it was a lot of work that was really unneccessary, especially since I thought to myself while doing it "boy, I hope this comes back out".
Oh well. good now.