rwolfe9

Thanks! Couldn't see that on my origional.

Props4ever

This is what you can do for hidden servos and linkages on Ailerons..

As for servos, you'll be ok with Hitec HS-645MGs servos, one/aileron for you 11 foot wingspan model.

aerofly0610

Found this thread.  I used to work on B-52s and one day hope to build a large sized ducted fan model.  Are you still working on this build?

clscale-RCU

My Feedback: (7)

The wing of the B-52 as seen in the photo can flex quite a bit, in reality the wing has 2.5 degree of dihehal and is set to 6 degrees angle of attack. When you sweep the wings back as seen from the top view, put some dihedral and then pitch them up 6 degres the wing looks like it has anhedral, but it does it not. The flaps are the typical flowler flaps, they move aft and down when they are extended, look at a good 3-view from the bottom and you will see the overall shape of the flaps.

Good luck.

rwolfe9

Yep, I'm slowly working on it. Right now I'm working on the LG with a lathe and waiting on SIG to send me my shipment of fiberglass so I can keep on with the nacelles. Was wondering, can you put monokote over fiberglass?[sm=spinnyeyes.gif]





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rwolfe9

Thanks! That reduces the trial-and-error time greatly!




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BMatthews

I've found that monokote doesn't like to go nicely over anything that isn't highly pourous. Like balsawood for example. Even appying over plywood tends to make it look nasty. You can try it but I think you'll find that painting the fiberglass parts is a far better option.

Props4ever

Hey Robart,

Good to know you are still working on the BEAST!, i wanted to ask your progress but other member already did. Post some pics of the current stages....n yeah, as Bmattews said, use primer and paint over FG, don't bother with plastic covering anymore. Most ppl want to glass there wooden models also, just so they can be painted and all sort of details could be added on the model's surface.



Sam

dkorzun

Ok, flew G and H models of the B-52 from 1987 to 1994. The wing - 185 feet tip to tip, can flex up to 17' from their position on the ground. The wing root is set at 6 degrees angle of incidence relative to the body line. Earlier models, up through the F I believe, used ailerons for roll control. Data exists for takeoff and landing at various flap settings and configurations including, if memory serves outboards only and inboards only along with no flap, though I never saw any of these non-standard configurations used. Besides the familiar hard points inboard of the inboard engines, there is another set of hardpoints between the inboard and outboard engines.
Ailerons were dispensed with on the G and H due to control reversal at high speed, so they went with spoiler/airbrake combination. The combs or fingers on the spoilers/airbrakes should be parallel to the fuselage on G and H models, not sure for previous models, they increased the effectiveness by creating interference drag. During air refueling airbrakes were usually set to the 2 (out of a max of 6) position to increase control effectiveness through differential input - as you turned the yoke, one set of spoilers retracts, increasing lift, the other extends further, increasing drag, reducing lift further. This was also done on approach for the same reason.
The fuel tanks on the G/H were not jettissonable and provided mass balance to twist the wing creating washout of approximately 2 degrees and also reducing/inhibiting wing flutter which created serious structural problems at high speeds. The larger wing tanks on the D models and other previous variants were jetissonable and held, I believe about 17,000 pounds of fuel.
Some thoughts to consider for creating at least the illusion of a flexed wing can be done by airfoil thickness selection. The actual aircraft had a fairly thick root section as a percentage of chord, this decreased significantly as you progress out toward the inboard engines. If you're creating a build up wing, you can accomplish this by creating a fairly sharp decrease in thickness ratio as you progress outward toward the inboard engines (think parabola). You will obviously find it difficult to create a wing that looks correct both on the ground and in the air due to the nature of how we build wings for model aircraft, and unfortunately I can't help you there.
I can probably provide information, with a little digging, as to the normal CG range. Also, the aircraft was pitch trimmed by moving the entire horizontal stab, with a fairly small actual elevator. You will probably want to design yours in a similar fashion so you can get in the ballpark for where neutral is, and then lock it down.
You may have noticed that the aircraft would climb with a relatively level deck angle, and tended to appear nose down in level flight - this is normal and is due to the incidence angle of the wing. For takeoff you had to apply back pressure on the yoke so the back wheels wouldn't lift off first leaving you wheelbarrowing down the runway (saw that happen during a touch and go back in the late 80's, aircraft drug a pod on the runway but otherwise was ok). Once the aircraft reached "unstick" (S2) you would apply additional back pressure to get airborn then relax back pressure to level at about 50 feet and accelerate to 180 knots, and start climbing and cleaning up. The wing flex was unnerving the first few low levels, but you eventually got used to it, though it was always interesting to be part of an air refueling formation and see how much bend was there after refueling to max in-flight gross weight. In many respects the plane is a huge powered glider. There are some PSS versions around of various scales.
There was only one drag chute, yellow in color on the B-52, the only bomber I recall having more than one was the XB-70 which had 3.
Some trivia, the first B-52G to return to Loring AFB following Desert Storm had it's drag chute adorned with a huge "smiley face" courtesy of their maintenance and life support units.
The vertical stabilizer on all B-52s is able to fold down to enable the aircraft to be hangared.

Good luck with the project.

rwolfe9

WOW! I could bother you for a long time! Thanks! You are correct, I do need the CG, but at the rate I'm going that won't be for another 2 years. Besides, we lost the airfield my club had to the Metro Parks, so I'll have to commute a distance for the maiden flight. I'm going to try to upload some pix now. Any and all suggestions will be greatly appreciated!


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rwolfe9

Here's the bottom side of one wing. I've covered it with Monokote, and will be glassing the LE. You can see the nacelle mounts and some of the supply wires hanging out.

rwolfe9

Here's the view from the top of the same wing. I got the idea from a pilot at our field to use an aluminim tube as a structural support and as a positive buss from the batteries. It also has a piece of #4 bare solid copper for the negative buss. The fuse has a hardwood backbone to support the tubing. Still no tip retracts.

rwolfe9

Here's my molds for the thrust tube/intake, and the top and bottom of the nacalles. I got the mold-release wax from SIG as well as .75oz and 1.5oz cloth. The tube is made from balsa turned on a lathe, primed, sanded, primed, and painted with egshel paint(what I had). After waxing, expoying with .75 and 1.5 (in that order) I need to slit the glass, but then it comes off just fine. The save can be said for the mold for the top of the nacelle. The only difference is the mold is made from 5oz and fiber tape. It releases fine. The bottom I made from plaster of paris and a box. Seemed to be a good idea. I let it cure, scraped/sanded to where I wanted it, primed, sanded, primed, painted with egshel. Then waxed etc as with the others. When I went to pull it out, big chunks of the mold came with it. Can someone tell me how to fix this, or should I make another glass mold like the top?

rwolfe9

Here's the one completed nacelle. I haven't started sanding/filling/painting yet, but the result turned out OK. The guts for it are made from 1/2 x 1/2 16ga aluminum and are riveted together. The next one I'll mig weld, just got the stuff for aluminum, will be a learning process. The fuse etc is going to be covered with aluminum Monokote and they make a spray paint to match, so I'll use that for the glass stuff.

rwolfe9

Here's the LG retracts. From the left, the tube is a shock, tires mounted with 12# rc buggy springs and the steering pivot tube, and the struts etc. I got hold of a jewler's lathe from Craigslist.com and it helps with the struts in a big way. I now can make the struts fit the tubes exactly with no play. It is the same design as the post I did last year. I would like some suggestions on the triangle shaped piece. I was able to duplicate almost exactly the angles and movement of the fullsize gear from a guy in California who supplied me with some pages from the 1954 B52 flight manual. I don't want to try to make the gear look exactly like the real stuff, but I'd like some suggestions for how to make this triangle piece look better.

rwolfe9

Last, here's the fuse with the other wing on top of it. I'm at a 12' span still, and haven't done much with this stuff for a while. Just working my way around to them. The whole plane as-is without the one nacelle and LG is just over 12#. Probably will be about 22-25 when done. I plan to gang up some laptop batteries from allbattery.com for the power. It's the same Li-poly batteries, and if you can make them, it saves you a bunch of $!



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