Mustang Fever

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Success!!

Those tricks worked out really well.

You can see from the closeup that the upper edge came out bonded real close, while there's a gap or two on the lower one. (Nothing that can't be disguised with careful sanding.)

Epoxied skin #3 awhile ago. Should be able to do the remaining side tomorrow morning sometime.

Quikturn

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WOW! that looks really cool Bob. I thought the wings were for the bullet though? I'd be interested to see how that flies. Is the bullet your design?

Mustang Fever

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The wings fit either the Arrow or the Bullet. The Bullet is my creation.

I'll probably end up using the foam core wings on the Arrow only, and reserve the built up ones for the Bullet. This is because the Bullet needs some countertorque weight in the right wing tip, and the Arrow doesn't like that at all.

Quikturn

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Also, foam core wings sound like a better idea for a sea plane.

How does the bullet fly? Any plans for it? Easy build? How does the F-16 style gear hold up?

Mustang Fever

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Yeah, with the wings living in the water the way they do on the Arrow, an open structure built up panel just gets beat up. Especially considering some of the terrible landings I've made the last two years.

The bullet is a hoot. Fast- probably around 90mph, and handles real smooth. I come over the fence a little nose high, carrying some power, then chop the throttle and haul the nose up when it gets close to the ground. Makes perfect F-106 landings everytime.

I have a basic sketch of where everything goes, and a template for the formers, which are all 5" wide except for the two way up front. There's a flat on both sides of the formers (5" wide) where the wings mount, the tops and bottoms are curved or flat, depending on where they are located. I drilled holes in the center of the formers so I could put everything together on a steel rod.

The simple, cheap mechanical landing gear has been 100%. I'm surprised.

The foamie wings are now reserved for the Arrow, and I'm keeping the built ups exclusively for the Bullet.

Mustang Fever

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Haven't worked on these for almost a week, as I was bashing an Extreme Flight Outlaw into electric power.

both cores are capped on all the edges and carved/sanded to final shape. I used short pieces of 1/2" square basswood recessed and epoxied into the lower wing roots as mounts for the attachment brackets.

I'm going to coat everything with thinned finishing epoxy and then cover.

More later.

Mustang Fever

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RTF. The weight penalty turned out to be exactly 10 oz- the panels weighed 5 oz more apiece than built up. I swapped the Macs muffler back onto the engine, which removed 1.7 oz from the tail, and it was still tail heavy, so had to add exactly 1.7oz in the nose.

Weather looks good for tomorrow- the lake is glass calm right now and a mild breeze is supposed to come up out of the East by flying time, around 830. Temp will be around freezing, but that's no big deal. The little OS 46AX cranks right up under those conditions and runs great.

I was out flying the little yellow electric in the background this afternoon.

Mustang Fever

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Well, my fingertips are still thawing out, but Arrow IV flew well, as expected. Conditions were 8mph from the SE, and 29-30 degrees. I had to get right at the east end of the lake to get calm enough water. It was nearly white capping over on the north side where I normally fly. The wind was so strong at about 100 feet that control in roll was marginal, at best. Every time I made a turn she tried to flip one way or the other, but I flew around for about 5 minutes, trimmed it, and landed. The Arrow and its sister, the Bullet, will always be my favorite sport birds.

Mustang Fever

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The Delta Duo

Mustang Fever

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OK, guys, here it is: first one to figure out what caused this damage and post his answer here gets a free lunch or dinner on me at Da Dawg House in Cadillac, MI. Hopefully you'll get to see the Arrow fly as part of the deal.

pmisuinas

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Iceberg???

N1EDM

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You hit a thin ice floe in the pond? The water was so smooth that you couldn't see it?

Bob

Mustang Fever

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Pete, you had the right substance, but Bob wins the prize. There was a thin layer of ice from shore out to about 50 feet this morning. I tossed a pebble out and it went right through, so flew anyway. There was plenty of open water a bit west of the launch point, and that's where I took off from, but the first landing was in the middle of the ice patch and that's probably what scraped her up. Ten minutes later, the ice was all gone.

Big testimonial for foam core wings with the outer skin coated in epoxy. I doubt the built up wings would have survived that first landing, and I would've had to come home instead of having some more fun.

If anything, the Arrow flies better with these new wings. They are a touch longer in span- maybe a inch or so- and the airplane seems to be happy with the small increase in wing area.

Bob- it's only 880 miles from Brockton to here. I used to drive that routinely when I was working. (I think Hertz Penske truck leasing was the customer, but I'm sure there were others.) Travel expenses not included with your prize. Sorry. [:-]

I had a buddy where I worked in Detroit 30 years or so ago who flew P3s out of SANGB with the USNR, Lt Cmdr Pete Madley. (Not sure on the last name spelling, but we used to call him Mad Man.)

N1EDM

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OK Rob, I should be there on Sunday to collect... if I can't make it, start without me - perhaps with a friend of the opposite gender

I hadn't heard of Mad Man (though it's a small community) but I've been in and out of Detroit several times. Too bad that it had to close. I flew out of NAS South Weymouth, MA and was forced into retirement. Us older guys just didn't want to get out and the younger guys coming in couldn't advance in rank. So, they made us retire, which was only right.

My fingernail marks are still on the doorframes up there.

I'll have you know that I just put a set of Arrow plans on order from RCM Plans this morning (reading this thread was bad for me ) and I think I might have a source for a short kit. The project will be down the road a bit, but I'll start to re-read this build thread.

I hope that the damage was only superficial, like it seems in the photos.

Bob

Mustang Fever

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Bob-

Yeah, just superficial. I'll have her RTF again in an hour or so.

Mad Man flew out of Selfridge when I was with the 191st FIG (F-4Cs). His missions were almost always during the week, tho, all day stuff out to the east coast and into boomer waters.

Don't forget the 5 degrees downthrust. They are a real handfull without it. The Arrow #4 build starts here, the earlier stuff is all before I removed my head from rectal defilade:

http://www.rcuniverse.com/forum/m_72...11/key_/tm.htm About 2/3s down the page.

You must be talking about the Lazer Works short kit, http://lazer-works.com/rcm.html $82.69. I have an unbuilt Super Kaos kit from them, and it is really pretty to look at.

N1EDM

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Our stuff was done both during the week and weekends. The cool part about it was that when we were on patrol, we weren't 'practicing' on our own boats (they wouldn't let us); we were doing real sub hunts on Boris himself.

I actually HAD forgotten about that down thrust. Thanks for the reminder. I'm going to check out that Super Kaos.. I didn't know that it was there... and I'll follow your link from page 11 too.

Bob

Mustang Fever

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Yeah, if you were in the cold war, you knew all about it. Our alert detachment at Seymour Johnson make approximately 200 intercepts on Bear bombers. Funny thing is, you try to tell anybody outside how bad communism is, they look at you funny.

N1EDM

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Yup, you and I are of a different generation and a different breed. This generation never had to practice diving under their school desks or hearing the air raid sirens go off on a weekly basis for tests..... Glad that we were there to help.

Don't want to hijack the thread... In a short bit, I'm going to re-read that RCM that has the Arrow in it. I'm also reading from that link that you sent me. Lots of good info that, I can tell, just from scanning it quickly.

As I said, the plans are on order.

Have a Happy Thanksgiving, Bob.

Bob

N1EDM

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Hi Bob,

I need an opinion... I re-read the RCM Arrow article last night, and I'm also re-reading your build sequence (Post 390). It started me thinking.

When I look at the wing section in the RCM magazine plans, the wing appears symmetrical. What would your opinion be about changing that to a semi-symmetrical shape??

Also, I see that you're flying with an OS 46AX. I was wondering if that was sufficient power for you , or if you'd recommend a 55AX in hindsight? What are you using for prop and fuel? I run my 55's with a 12x6 prop on 10% fuel.

I'd be curious about your thoughts on these... and you may have already addresssed them. I haven't gotten to page 12 of the build thread yet. going to read a little more of it now, then back to making the Thanksgiving turkey!!

Bob

Mustang Fever

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Bob- Happy Thanksgiving to you.

I don't know if there would be any advantage to a semi airfoil. The way it is, the wing can be built flat on a board, which really simplifies things. (I didn't, but that's another story.) Another thing about that airfoil you may have noticed is that it is very thick near the leading edge, and tapers rapidly aft. I think this is essential to the stability of the delta wing, and I don't know what would happen if you changed it. (I have an Extreme Flight Outlaw delta, and it appears to have the same airfoil.) Laddie, if you see this, please chime in.

The built up wings do take a beating, so you might want to look at getting the foam cores from flyingfoam.com. Constructing them is near the end of this thread.

I chose the 46AX because, with a Macs Muffler, it is the lightest engine in that power class. I used much heavier engines in my first two Arrows (a Tower 46 and an OS 55AX) and both suffered due to the amount of ballast I had to put in the nose to get the CG right, as the big battle with this design is that they build tail heavy. I researched using a Jett 35. The performance would have been a little better than my 46, but the weight savings was very minor (max 1 oz) and the fuel consumption to get that performance would have been much higher, along with the expense.

My 46 turns a 10x6 APC at 14,500 rpm on 15% Cool Power. That's good for 83mph and over 6 pounds of thrust. On an 8 oz tank, she'll fly around at close to half an hour if I manage the throttle a little. It's pretty noisy, but that doesn't seem to be much of an issue at lakes.

Hope this helps.

rocketman-RCU

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Did I ever show you guys my Byron Jet version of the Arrow

Mustang Fever

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That is too cool. How does it fly?

Strykaas

Awesome ! Please keep the pix coming [8D]

N1EDM

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Thanks, Bob. I'll keep that in mind. I had actually had thoughts about converting a BTE Engineering Delta Vortex. But, I'll keep what you say in mind. OK, symmetrical it is. I was actually surprised that a .46AX could pull this around with a 10x6 prop, but based on what you say, I'll go with that.

Thanks for the input. I think I ate too much Thanksgiving Dinner today...

Bob

Mustang Fever

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I know I did.

Another thing to look out for is the boxes that the plans have you build to plug the wings into. They are really difficult to build, and don't work very well. I found that 1/2" OD aluminum tubing with 1/16 wall thickness fits the 3/8 CF wing tubes perfectly. By fitting the wings onto the tubes, and then tacking the tubes into place on the formers with CA, I was able to get them nicely positioned on the Bullet. Then I went back and stuck em in place with a mixture of epoxy and milled glass. The supplier where I got my CF tubes - dragonplate.com - now has some larger tubes that would perfectly nest the 3/8 ones and save you a little weight.

The only other structural things I can think of have to do with the aft deck, the bottom forward of the step, and the stress concentration at the aft lower corners of the hatch.

I used 1/8 lite aircraft ply for the aft deck at the base of the fin, and for the bottom forward of the step all the way to the nose block. These areas take a beating from vibration and water pounding.

It's critical to reinforce the inside of the hull sides forward and aft of that lower aft hatch corner, as a hard landing will result in cracking the hull sides at that point all the way down to the waterline. Then the nose tries to fall off.