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  #11  
Old 01-03-2015, 01:04 AM
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mbauer mbauer is offline
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Gluing the Wing Ribs

Time to glue the wing ribs to the Leading/Trailing edges and Spars.

For gluing to the cardstock leading edge and trailing edge, Alene's Turbo PVA is used (just tried Zip Dry glue and love it-however it is highly flammable-not much use on a blue-flame thrower!).

Photo 25 shows how I cheated to keep the ribs in the proper shape when gluing the ribs to the spars. Ribs are already glued to the leading/trailing edges. Had to use super glue on the trailing edges, not to happy about that.
Buzzzzz 2 Pulsejet Paper Airplane-25.jpg

Photo 26 shows a wide angle view and the best item you can use when doing any kind of epoxy work: Wax Paper! Work great for a release on the spar lay-ups to keeping excess epoxy off of the work surface.
Buzzzzz 2 Pulsejet Paper Airplane-26.jpg

Photo 27 shows the wing positioned vertically for the actual epoxy fillets from rib to spar. Notice the double use plastic ruler..
Buzzzzz 2 Pulsejet Paper Airplane-27.jpg

Photo 28 shows the fit test of the outer fuselage to the wing. Yes, there needs to be a final carving to the wing airfoil shape to get the fuselage to fit properly.
Buzzzzz 2 Pulsejet Paper Airplane-28.jpg

Photo 29 shows the wing fit test to the wood power skid after the wing structure has been glued (ribs to spars).
Buzzzzz 2 Pulsejet Paper Airplane-29.jpg

More to follow.

Mike
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  #12  
Old 01-03-2015, 02:33 AM
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Epoxy Wings To Power Skid

Time to epoxy the wings to the power skid.

A confession: Forgot to design the wing length to account for the thicker 1/4" wood power skid. This added a 1/4" to each side, or 1/2" total. There is a gap between the wing halves where they meet in the middle. Ouch!

Quick fix is to print a new middle piece to patch the gap. Will see this in future photos.

Photo 30 shows one last look at fitting of wings to wood. Without the wing skins don't realize the above issue yet. This is the last photo just before the epoxying happens.
Buzzzzz 2 Pulsejet Paper Airplane-30.jpg

Photo 31 shows wings as epoxy is curing, notice item behind pulsejet in the background? White cylinder tube is the inside fuselage support. Gives the fuselage strength and helps keep the round shape. Sorry, about the bright LED light...Only used this photo to show the fuselage support-only photo with it in it.
Buzzzzz 2 Pulsejet Paper Airplane-31.jpg

Photo 32 shows all screws in heat shield to verify it fits with no issues. Wings are solid to the wood frame, only thing left to do is a fiberglass layup to join the spars in the middle. weight with everything on top of scale is at 3lb 3.7 oz.
Buzzzzz 2 Pulsejet Paper Airplane-32.jpg

Quick weight test is next!

Mike

Last edited by mbauer; 01-03-2015 at 03:29 AM.
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  #13  
Old 01-03-2015, 02:44 AM
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Weight Testing! Will it Break?

Weight testing without wing skins. Hoping for around 10 lbs, if model weighs in at a round 3lbs 4oz, this means it will have a 3 G load limit. 15lbs will give an approx. 5 G load limit.

Some problems popped, loose!

Photo 33 shows 15 lbs being supported by the wings and front edge of power-skid. Notice the trailing edge super glue didn't hold on several ribs!
Buzzzzz 2 Pulsejet Paper Airplane-33.jpg

Photo 34 shows wing flexing but not breaking!
Buzzzzz 2 Pulsejet Paper Airplane-34.jpg

Photo 35 shows 30lb center wing section testing. You can see the fiberglass lay-up of the front wing spar connection. Front and back were lay-up using 3 layers on each connection and then 2-more layer added going to the wood sides. You can also see the dark wood dowel that was epoxied in to also make sure the connection stays together = Strong!
Buzzzzz 2 Pulsejet Paper Airplane-35.jpg

Fixing /covering the wings is next!

Mike

Last edited by mbauer; 01-03-2015 at 03:31 AM.
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  #14  
Old 01-03-2015, 02:53 AM
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Fixing Trailing edge Glue Connection & Wing Covering

Time to fix the trailing edge that popped loose from the ribs. Hard time trying to figure how to clamp. Rubber bands and super glue to the rescue!

Just enough pressure using the rubberband, a small drop of superglue to hold and viola, perfect clamp for delicate work!

Photo 36 shows rubberband clamp in action!
Buzzzzz 2 Pulsejet Paper Airplane-36.jpg

Photo 37 shows rubber-band clamps holding wing skin down to ribs. Used Alene's Turbo Tacky by applying to each rib (top & bottom) front leading edge as well as rear trailing edge. Not much to see, except for the rubber-bands. Cut each band and tied them end to end to get a long "clamp", final tie was used to create the right amount of pressure. Worked great!
Buzzzzz 2 Pulsejet Paper Airplane-37.jpg

Attaching the fuselage is next!

Mike
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Old 01-03-2015, 02:59 AM
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Attaching Fuselage

Ok, right off the bat made another mistake. Fuselage fit test earlier with no problems. This time it ripped, bad! Had to reprint a new one.

Photo 38 shows the tear!
Buzzzzz 2 Pulsejet Paper Airplane-38.jpg

I do not like gluing cones! Oh well!

Photo 39 shows gluing fuselage top to wings. Alene's worked great once again!
Buzzzzz 2 Pulsejet Paper Airplane-39.jpg

Photo 40 shows left side getting glued.
Buzzzzz 2 Pulsejet Paper Airplane-40.jpg

Want to see what it looks like?

Mike
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Old 01-03-2015, 03:09 AM
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Final Shape!

Ok, here it is!

Photo 41 shows the rudders drying. Elevons have been taped on using heavy duty clear repair tape. Simple!
Buzzzzz 2 Pulsejet Paper Airplane-41.jpg

Photo 42 head on look.
Buzzzzz 2 Pulsejet Paper Airplane-42.jpg

Photo 43 shows looking down at it. Notice little servo tabs sticking through the wings? These are the Elevon hook ups.
Buzzzzz 2 Pulsejet Paper Airplane-43.jpg

Photo 44 showsRight side view
Buzzzzz 2 Pulsejet Paper Airplane-44.jpg

Photo 45 left side view
Buzzzzz 2 Pulsejet Paper Airplane-45.jpg

Views of inside electronic mount are next.

Mike
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  #17  
Old 01-03-2015, 03:27 AM
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Electronics Inside views

Radio Receiver and Switching BEC are shown in these views.

What is a BEC? It allows a battery to be connected to the receiver. Most models have a throttle that the battery hooks to and then from the throttle it connects and supplies power to the receiver. The more throttle you give the more juice to the receiver.

Without a throttle, if you hook the battery directly to the radio, you will fry it! It can handle 6-volts and that's it! My battery is a Li-Po that is rated at 11.1 volts.

The BEC takes the battery voltage and drops it to 6 volts or 5 Volts if you switch the jumper.

Photo 46 shows the radio and BEC. BEC is on the side mounted with Velcro. Velcro also holds the radio in place. Not much weight for either of these two items!
Buzzzzz 2 Pulsejet Paper Airplane-46.jpg

Photo 47 shows everything from a different angle. Notice tight fit for everything. White tube like device is the antenna. You can also see inside fuselage support.
Buzzzzz 2 Pulsejet Paper Airplane-47.jpg

Photo 48 is a final look at the interior
Buzzzzz 2 Pulsejet Paper Airplane-48.jpg

total weight at this point is 3lbs 4.9 oz. Engine puts out 3.53 lbs of thrust. This models weighs less than the thrust, so yes, it can probably go vertical!

Notice I limited the fuel tank size? Engine says to use a tank three times bigger than this one. My thoughts are a quick climb to altitude and then a glide when the fuel runs out. Level flight at speed might rip the paper!

Once a pulsejet is running, there is no throttle! Wide open or it quits.

Photos of it running, if I can get it started. Other photos and videos as it takes the leap from the nest. Thinking of adding landing gear instead of using a catapult.

Thank you for looking at my recent build, hope you like it!

Mike
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  #18  
Old 01-03-2015, 08:21 PM
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Specifications:

Forgot to mention a couple of things:
1) Pulsejet mount can be moved left to right and exhaust can be move up or down for down thrust if needed
2) In the photo there is a white piece of ceramic paper for insulating the hot engine mounts from the heat shield. You can see it as a white band under the front mount.
Buzzzzz 2 Pulsejet Paper Airplane-46.jpg

Specs:
Redhead Pulsejet from Hobbyking:
Length = 21.65" / 550mm
Diameter = 2.52" / 64mm
Weight = 1.01lb / 460gm
Thrust = 3.52lb / 1.6kg or 1600gm
Cost: $99 + shipping (included an electronic ignition device)

Model:
Wingspan = 49" / 1244.6mm
Length = 24" / 609.6mm
Length w/pulsejet = 36" / 914.4mm
Weight = 2.3lb / 1043.26gm
Weight w/pulsejet = 3.31lb / 1501.39gm [1.5kg]
Each wing weighed 7.6oz / 215.46gm each before covering

Started to install control linkage, can't find my control horns for the Elevons. Minor delay until I can drive to the local hobby shop 30-miles away.

Bought some years ago and lost them during one of 5-moves!

At least I can hook the fuel line up and see if it starts! Will try to take photos and a short video if it runs!

Mike
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  #19  
Old 01-04-2015, 04:30 PM
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Elevon Control

Took a couple of hours of searching through many boxes from my last move. Found the Control horns.

Using the horns, 1mm carbon fiber rod, and the linkage shown, finally have controls rigged.

Installing some fairleads over the open holes in the wings where the servo arms stick up. Enlarged the holes to allow proper movement of the arms, without binding.

The fairleads are there to stop the wind from getting inside the wing and causing it to balloon. Might even tear it up once it gets to speed. Fairleads are needed.

Photo 49 shows the fairlead on the right side in place. After the first glue dried, went around the fairlead with another bead of glue as shown. Don't want the wind to get under it!
Buzzzzz 2 Pulsejet Paper Airplane-49.jpg

Photo 50 shows the size of hole the fairlead is covering, this one is next on the left wing.
Buzzzzz 2 Pulsejet Paper Airplane-50.jpg

Photo 51 shows what the fairlead looks like from a distance.
Buzzzzz 2 Pulsejet Paper Airplane-51.jpg

Hopefully these fairleads won't cause any flight issues!

Fuel system is next!

Mike
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  #20  
Old 01-07-2015, 05:04 AM
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Fascinating thread!
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