invertmast

My Feedback: (23)

well, my New in Box BVM Ultra-Viper kit arrived today. I've been getting more and more interested in the high power EDF's and after seeing the electra's fly with the new EVF-2 i decided it was time to get something that would fit in the back of my truck and easiest enough to be able to fly after work. So the hunt started for a U-viper to convert, after not finding any used airframes, i found this new kit and landing gear. So i figured i would start up this build thread. Plans are:
BVM air operated gear w/ trailing link struts
JR 3421's on flight surfaces, 9411's on flaps.
Separate Flaps and Ailerons (no flaperons)
BVM EVF~2~ on 12s will probably try out some of the XPS jet-packs if they will fit. I'll get a few TP packs as well.

I'm still completely undecided on a color scheme, but i think its going to be a mixture of a sport jet and some scale jet stuff in there as well (panel lines, flight metal, etc etc). Suggestions on a color scheme are welcomed

First thing i normally do when i get a kit that has full size plans is hang them on the wall. Then work begins.The spars and flex-plates were already installed when i got it, but thats the only work that had been done. I got the filler material and leading edges put on.





With foam core wings, I prefer to tape off the sheeting adjacent to the area's that are going to be sanded. This includes wingtips, leading/trailing edges and any other area's that has an item that needs sanding.

I also went ahead and rough-cut all the fuselage cutouts as well while the wingtips dried. I am planning to run separate flaps and ailerons on this viper, as it will make it handle much better as the flaperons are supposedly not very effective at slows speeds. I have a rough idea on the dimensions for the new layouts, but will wait to post up those dimension and a photo of the layout until I can verify some measurements.

invertmast

My Feedback: (23)

Picture 1: The top of the wing trailing edge is tapped off with masking tape flush with the wing skins. the bottom has 2 layers of masking tape overhanging the wing skins by about 3/8".
Picture 2: Here you can see a .010 x 3/16" Poly ply skin butted up against the wing trailing edge
Picture 3 & 4: this shows a slurry of 30 minute epoxy and micro-balloons put on top of the poly ply piece. The consistency of the resin/MB mixture is about the same as peanut butter:
Picture 5 & 6: This shows the initial sanding of the epoxy/MB mixture. And a close-up of the "razor thin" trailing edge before final sanding
Picture 7: The horizontal stabs and Vertical Fin getting the trailing edge workout the same as the wings. The one difference I made with these, is i overhung the bottom layers of masking tape by 1/2" and then folded the masking tape up along the edge of the poly ply strip. This made a "dam" to keep the resin from flowing away from where i wanted it.
Picture 8: Inlet ducts ready for joining and wrapped with carbon Tow. I haven't decided yet, but i may end up putting a 1" wide strip of 3k carbon cloth on the inlets as well to make sure they dont collapse.
Picture 9: The nose gear door and Bottom hatch outlined with masking tape
Picture 10: The nose gear mounting forum was originally 2 pieces of 1/8" light ply that were laminated together. I wasn't very happy with the material supplied as it was very weak. I had some 3/32" dragon plate laying around, so i substituted one of the 1/8" light ply parts and made one of of dragon plate. Not only does it look cool, its much stronger.
Picture 11: BVM Purple nose gear unit mounted to the flex plates and nose gear former. Its typically normal to have to spread the flex plates apart to get the nose gear screw holes to line up with the retract. I believe that the purple unit may be just slightly wider (1/16" or so) than the older units the plane was designed for, as the nose gear bulkhead is bowed about .010-.015" in the center with the nose gear mounted in the flex plates. I'll pull the flex plate assembly back off the bulkhead tomorrow and adjust the flex plate mounts to relieve some of the pressure on the bulkhead.

invertmast

My Feedback: (23)

so i've got a question for everyone. In the thought of attaining max speed out of this thing. Should i go through the hassle of shrouding the flap, aileron, elevator and rudder hinge lines?
The flaps will definitely get done, as they will be hinged like a slotted flap, so the shroud will need to be there. But everything else, im wondering if the benefits would out-weight the hassle of doing.

k_sonn

My Feedback: (32)

Looking good Thomas. Can I have her back when you're done?

I would shroud the hinge gaps. It would help with control responseat high speeds and it would also help to prevent flutter.

You asked for scheme suggestions. Here's the schemes I did on the two Electras I built. The camo scheme was the first one I built. It had recessed panel lines andburnt in rivets. I used the sport jet hatche covers from Pro-Mark. All of the markings were painted on. On the second Electra, I used a paint that changed from blue to red, depending on how the light reflected off of the surface (even on cloudy days). It was also partially covered with Flite Metal. I used the rub on rivets, panel lines, and hatch covers from Pro-Mark.

Kirk

hooker53

My Feedback: (106)

This is gonna be Niiiiiiiiice. Man, scrap the Batts and get a 44. Ha. Ha.

invertmast

My Feedback: (23)

Kirk,
Hadn't even given the flutter issue a thought, it completely slipped my mind. I think i'll be doing the control shrouds. it'll only be an extra hour or 2 of work and i've got plenty of time to get this thing done. I like the flite-metal idea. I was thinking of doing flite-metal nozzle "petals", wing leading edges and intake lips. I thought it would give a cool and different look to a sport jet. I like the flip-flop paint as well, but I have heard its a paaaiinnn in the butt to get right. what are your thoughts?


LOL roy. It would probably be cheaper going with a Wren, but the attractive thing w/ the EVF is puttin the jett in the back of the truck and flying after work without having to haul a trailer full of support equipment.

invertmast

My Feedback: (23)

Well, got back to home from work about 6am this morning.. worked on the U-viper a bit, and waiting on my down-draft table to show up, the shop is WAAYY to dusty. lol I'll get some pics up later.

Does anyone know if their is a set of metal gears that will work in the JR 8231? I bought 4 by mistake (confused them with the ones i really wanted), so i'd like to cut my loss' and upgrade the gear sets to metal and still be able to use them.

invertmast

My Feedback: (23)

Ok, lots of progress and pictures:

Picture 1: .007 Carbon strip re-enforcement on the wingtips. I used G10 on the stab tips
Picture 2: Shaped wing-tips
Picture 3: Layout of flaps and ailerons on wing panel
Picture 4: Flaps, elevators, Rudder, Stabs and vertical fin all getting 'capped" with their leading, trailing and root/tip balsa parts
Picture 5: EVF2 shroud mocked up with the inlets
Picture 6: Shrouds getting glued together and shown wrapped in peel ply (100% polyester cloth) to soak up the extra resin
Picture 7: Close up of the peel ply cloth showing how much excess resin was soaked up
Picture 8: Bottom hatch and nose gear door removed from the fuselage
Picture 9: Nose gear bulkhead and nose gear test fit.
Picture 10: Different view of #9.
Picture 11: Stabs and elevators ready for hinging
Picture 12: completed Inlet duct ready for installation
Picture 13: Test fit of inlet duct looking in from canopy hatch
Picture 14: Test fit of inlets looking in from power hatch
Picture 15: Hinging elevators and rudders. These are now essentially complete except for adding the poly-ply "shrouds" over the hing lines and installing the torque rods. I also have to cut out the area for the rudder servo once that arrives.

The wings need to have the trailing edge capped with balsa and the leading edge of the ailerons capped. Then i can hinge the flaps/ailerons, cut out the aileron servo pocket and finish up the wheel well area, and the wings will essentially be ready for glassing.

hooker53

My Feedback: (106)

Looking good Invert and welcome back to earth!!! lol

invertmast

My Feedback: (23)

Todays work includes getting the wing TE capped, the aileron LE capped and the flaps and ailerons hinged. the fuselage is also completely ready for bulkhead installation, and the inlet duct is ready to be installed to...

Picture 1: Shows "pockets" cut into the foam trailing edge of the wing for 1/2" square balsa blocks to get epoxied into. These are only in place for the flaps, as the 1/2" thick balsa TE should provide enough "meat" for the aileron hinges
Picture 2&3: Both wing panels showing the completed "capping" of the Trailing and leading edge's.
Picture 4: Interior view of the drill jig for the flap hinges.
Picture 5: Completed view of the flap hinge drill jig. Sides are 3/32" plywood, with a 3/16" balsa core. then 1/2" balsa is glued on both outside edges to assist in holding the jig perpendicular to the trailing edge. I typically put a brass tube the correct size for the 3/16" drill bit, but i didn't have one, so i skipped that step.
Picture 6: A view of basically what the drill jig will do.
Picture 7&8: Bottom view of left wing with flap/aileron hinged. Aileron still needs its LE shaped.
Picture 9: Side view of the flap in its "down" position. I will end up doing a 1/2 round on the flap LE so the air coming through the slot in the bottom will transition around the flap nicely. I'll then use poly-ply to "seal" the gap left on the top of the wing when the flap is up.
Picture 10: Top view of the left wing with the flap down.
Picture 11: The best shot i could get of the razor (literally) thin trailing edge on the wings.

k_sonn

My Feedback: (32)

Looking good Thomas.  Nice idea on the flap hinge drill jig.

Kirk

invertmast

My Feedback: (23)

Got the Aileron and flap hinge gap seals in place today. the first wing took about 2 hours to do, but the other wing only took about 30 minutes... its amazing how quick things go once you figure it out. I could of had the first wing done sooner, but ran into some issues...

I remember someone asking me to show how i did the gap seals, so here is a series of pictures and write-up on how i do it.

Picture 1: The First thing i do is take my little sanding jig/tool and place a strip of self adhesive sandpaper onto the bottom of. The sanding tool is just a 1"x4" piece of 3/32 aircraft ply, w/ a 3/8" balsa tri-stock piece glued to one of the 4" edges and all of the exposed edges/corners rounded. then a handle is glued in the center of the ply on the opposite side of the tri-stock. The sandpaper strip is the same width that you plan to over-hand your poly-ply/G10 gap seal. In my case, i used 0.4"

Picture 2: This shows the sanding tool jig placed on the trailing edge of the wing after the sanding has been completed. You'll notice the tri-stock is not "flush" with the trailing edge. The tri-stock is only their to keep the tool parallel to the trailing edge. You want the piece of ply to be resting on the wing-skin and trailing edge piece, this way your "groove" is the same depth along the entire trailing edge.

Picture 3: This is a photo of the groove in the trailing edge with the sanding tool removed.

Picture 4 and 5: This shows a .015" poly-ply gap seal in place, and this was the mistake i mentioned earlier. After getting both the top and bottom seals for the aileron in place, i realized that they were far to stiff for the aileron to get more than 1" of surface deflection w/o having a large "gap" between the seal and the aileron. So these .015" pieces were removed and replaced with .005" pieces. this allows a wider gap seal to be installed so their is no gap left at all now.

Picture 6: if you look at the far end of the aileron, you'll notice the gap with the .015" poly ply pieces.

Picture 7 & 8: The new .005" poly ply pieces are installed. You'll notice the gap is completely gone the full length of the aileron.

Picture 9: is a photo of the flap leading edge with the upper corner rounded off

Picture 10: The wing with aileron seals complete and the flap in place and waiting for its gap seal to be installed.

Picture 11: shows the completed wing panel. the .015" flap gap seal is sanded to a "knife edge" on the bottom of the trailing edge of the seal. The reason for this, is since the poly-ply is so thick, the taper at the trailing edge makes for a nice blend of the seal into the flap.

Picture 12: A view from the root of the wing panel showing the flap gap seal. The taper is not really visible in this photo.

Picture 13 is a view of the bottom of the same wing. You can see how tight the flap seals to the wing trailing edge and the lack of the gap with the aileron and wing. I may install a .005" seal on the bottom of the wing over the split line of the wing/flap to seal that gap as well. It really just depends on how tight of a seal i can get after glassing that particular area.

Picture 14 shows the foam removed from the wheel well area's. The foam left in the perimeter of the wing bays will get blended into the walls, and then 3k carbon cloth will get laid in place in all 3 bays. One thing i was not aware of, is that the interior side of the wing-skin already has a layer of fiberglass cloth between it and the foam core. just goes to show ya how far BVM was ahead of everyone else 15 years ago or so when this kit was made.


I also have 5-JR DS378's on order for the flaps/ailerons and rudder so they should be here friday. That will give me all the radio gear i'll need save for a few extensions and a power switch. I need to get some wheels and trailing link struts (anyone have the length of an electra strut, so i can see if the length's are the same?). So I pretty much have 90% of the stuff needed to complete this thing. i just need to come up with the $$$ for the EVF unit and batteries..

















The wheel well area's had the 3k carbon laminate installed (picture 1). The Nose gear former F1 and the forward flex arm mounts were tacked glued in place (Picture 2). Picture 3 shows the top center BVM hatch pin, and a pair of 1/8" carbon rods used on the bottom corners for the power system hatch. Picture 4 shows the completed power hatch installed. The tedious trimming, sanding, fitting, trimming, sanding, fitting, rinse repeat process proved worth it, as their will be very little filling needed along the split lines.

Then came time to start on the canopy hatch. Some people prefer to do a pair of canopy hooks at a time. i personally prefer to install all the hooks in place at once and adjust the openings (already cut out in the fuselage flange) to allow the hooks to go through its mating flange. Picture 5 shows the canopy in place and taped so the edges are as close to flush as possible. Then the fuselage is rolled inverted and the canopy edge is pushed flush with the fuselage side (if it isn't already) in the area's where the hook slots are, then using a sharpie marker, the hook slots are traced inside of the cut-outs onto the canopies flange (picture 6), this is done all at once along the length of the hatch for all of the hook slots. What you get when you remove the canopy is seen in picture #7. Then all of the hooks are installed into the canopy (picture 8). The canopy is then placed back onto the fuselage and the slots in the fuselage flange are adjusted so the canopy installs nice and easy (picture 9). once the fit is correct, the canopy is then taped back to the fuselage and the power hatch is installed and the 2 hatch's taped together so they match up. Then plywood slot wedges are installed between the hook and the fuselage flange, these wedges "suck" the canopy down tight to the fuselage (picture 10), And in picture 11 you can see the nice tight seams between the canopy hatch and the fuselage. Again, this area will require very little to no filler to blend the hatch and fuselage together.

smaze17

My Feedback: (60)

Beautiful work dude......just beautiful!!

SM

BaldEagel

Interested to know why you did not go for live hinges and covering in Pro Skin?

Mike

invertmast

My Feedback: (23)

Live hinges i have never seen done before on a foam core wing.. I have also never seen someone cover an already sheeted foam core win with pro-skin as well... Those are the main reasons, otherwise i'm up for trying new things, i just have never seen either of them done on a sheeted foam wing before.

invertmast

My Feedback: (23)

First thing first for today, was to install the inlets. Not a whole lot to this. Just mixed up some 30 minute epoxy and milled fibers to a mayonaise like consistency. Spread it onto the flange of the inlet, then placed the inlet into the fuse and into position and block up the back of the inlets 1 1/8". I am very pleased with how it came out. Their is very little filling to be done to the seam. I wish i could say that i was responsible for this, but BV's moldings are exceptional and fit perfectly.



And of course the cursory Fan shroud test fits:



I then began the process of installing the wings. First thing first was to test fit the wing spar bulkheads F2 and F3.



once the fit was correct, i slide the wings on, made sure the wing root lined up with the fairing on the fuselage and set the dihedral and tack glued the spar receivers to the spar bulkheads. this was done for both wings.



The bulkheads were then removed and the carbon wing spar receiver doubler was epoxied to the back side of the bulkheads, and then the holes were drilled for the receiver attachment bolts and the spar double tapped to 4-40 and the bolts installed. (sorry, no picture)

I then placed the wings back onto the airplane to double check the fit and to tack glue the F2 and F3 bulkheads in place





I deviated from the manual a bit and decided to go ahead and install the F4, F4a, F3a and carbon elevator mount brackets, that way all of these parts could be hysol'd to the fuselage at one time. I didn't get any pictures of the fitting process, but it was simple.
I am planning to setup each servo in the plane and mix them together and use the balance function of my 11X. So i drilled out both sets of holes on the F4 and F4A bulkhead and double. That way i can use any combination of upper/lower, both upper, both lower, etc to get the mechanical geometry of the elevator surface deflection as close to possible. Once all the parts were hysol'd in place, this is what the structure looks like (sorry for the blurry pictures, my camera doesn't like balsa dust floating around)


while all of that stuff sets up, I decided to start getting the stabilizers ready for mounting. I traced the outline of each stabilizer onto the fuselage, making sure the leading and trailing edges were lined up with the "dots" on the fuselage. I then scuffed up the carbon stabilizer spar with 80 grit sandpaper and epoxied it and a balsa wedge into ONLY one stabilizer.


After the spar dried i did a cursory mock-up of the stabilizer to the fuselage. All is looking good at this point and the U-viper is beginning to look more like a jet instead of a bunch of parts.


And since ive got alot left to do, but not much can get done to the fuselage till the hysol cures, i decided to start fitting the main landing gear. These are a hybrid BVM system they have all BVM "internals" but utilize a set of custom machined aluminum frames that incorporate a air cylinder mount.
To them them to fit, i had to remove 2 very small areas from the flex plates (so the pivot actuation arm and air cylinder would clear) and pretty much all of the ply from one of the lite-ply wheel bay ribs (this is another reason for all the carbon in the gear bay).

smaze17

My Feedback: (60)

Really enjoying this thread Thomas!!! Can't wait to see the finished product!

Spence

Johnny9390

My Feedback: (34)

Where did you find the U-Viper kit? I am looking for one aswell. If you know of another one somewhere I would LOVE to have it!

Johnny

invertmast

My Feedback: (23)

I put a post here in the forum looking for one, and someone happened to be willing to let the one go they had.

LGM Graphix

My Feedback: (22)

I love the Ultra Viper, I personally still don't get the draw to EDF, but to each their own, your building is awesome, and fast!!!! Can't wait to see her finished!

invertmast

My Feedback: (23)

Jeremy,
I know what ya mean about the EDF draw. To be honest, a year ago i wouldn't of even thought i'd be doing a big EDF. Power system and battery costs are high. But with work getting more and more busy every year, it is beginning to get very difficult for me to be home on a weekend where i can devote a day or 2 to go out and fly the turbines. So i decided to bite the bullet and purchase this and all the EDf stuff, as i can just put it in the back of the truck (assembled) and take it to work and fly during lunch at work (at the airport the company owns) and then after work. and the only thing i need is an air-compressor, batteries, jet, tx and a charger.

Ya got any recommendations on a color scheme?

LGM Graphix

My Feedback: (22)

Hey Thomas,
I certainly get the appeal of throw it in the air and go, work hasn't been that busy for me, so I guess that's maybe why I can't wrap my head around the cost of the high end EDF stuff like this. It's cheaper to buy a Kingtech K80E than fan and batteries LOL But, a year ago I never thought I'd have a foam EDF either and yet I love my Habu, I don't think I'll ever go big EDF as there is still no place local to fly it and to drive to the jet field at 2.5 hours away, I'll take turbines, wish I had the option of a runway at lunchtime! haha.

As for color schemes, just please don't do a typical BVM scheme, between Bandit ARF's, Electra's, and Ultra Bandits, I'm soooooooo sick and tired of the same old swoops, swooshes, and swizzles......

You could always do something like my old Spectre, that would look good on an Ultra Viper!





Of course, just a "Viper" red with some markings looks good too

gunradd

My Feedback: (9)

That spectre is sweet! I have almost a 2 hour drive to fly a turbine thats why EDF is so nice. I can go 15 mins down the street and fly with my EDF and not have to worry about burn bans and such.

invertmast

My Feedback: (23)

i agree with ya on the bvm schemes, I'm tired of them to. I was thinking of maybe an aggressor style scheme, but they seem to be getting popular on just about everything. Another thing I have to keep in mind, is I am hoping I can get this thing to do 200+ on the regular evf on 12s, so I can out run some electras with the "R" fan. Lol so a scheme that will be visible will be needed as well, which an agressor scheme isn't... ohh the decisions

k_sonn

My Feedback: (32)

Jeremy, I agree with you.  Large, high powered EDF's aren't for everyone.  Besides, I don't think we could get an EDF to go fast enough to capture your attention

Nice work Thomas.

Kirk