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Oct 12, 2011, 10:20 PM
Space Coast USA
hoppy's Avatar
Thread OP

Yes, IPA = isopropyl alcohol or you could even use
a damp rag. IPA dries quicker and may remove more surface contaminants.
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Oct 13, 2011, 01:00 PM
Addicted to building...
Freddie B's Avatar
The straight edge checking is nice, but if you glue appropriate sand paper to a real long piece of sanding block, say MDF Board, you can sand, align, and check the results all at the same time. Just a thought, I do this on FFF, balsa, and other structures.
Oct 15, 2011, 01:57 PM
Space Coast USA
hoppy's Avatar
Thread OP
Thanks Freddie, I'll give that a try.

Things going a lot faster on the other side as all I had to do was copy the left side bulkheads.
Pictures 1, 2, 3
Bent pins are used to line up the right side horizontal with the left side pieces.

Picture 4 - Right side bulkheads glued in.

Picture 5 - Servo tray and servo test fitted.

Picture 6 - Push wire guide (straws) inserted. Will probably run a proper nylon tube inside of the straws but needed to make the path before covering.

Maybe by the holidays.
Oct 22, 2011, 06:36 PM
Space Coast USA
hoppy's Avatar
Thread OP
Started the body sheeting. Using a new method (for me) for attaching the panels. Since they are curved, it's hard to hold all sides down at one time. My solution was to apply FoamTastic glue (long drying time) to the curved bulkheads and use hot glue to attach the bottom to the horizontal element. After a min or so after the hot glue had set, the panel was bent into the final position using pins and tape, pretty easy since one end was fixed and the long dry time glue was already in place.
Oct 28, 2011, 12:22 PM
Space Coast USA
hoppy's Avatar
Thread OP
Fuselage has been puttied with Light Weight Spackle and the back 1/2 is ready for brown paper covering.

The elevator is being assembled. 4mm carbon fiber tubing is being used. 1/2 of the joiner area was cut out and a hot soldering iron with a ball tip was used to make a round depression in the elevator 1/2s. After sanding the CF tube, it was epoxied into the elevator and held in position with tape.
The remaining edge of the hinge line will be contoured to match the CF tube outline.

Neat find at Dollar Tree. An air tight jar with a quick release lid. Filled it with calcium chloride to remove moisture and am using it to store gorilla glue.
Oct 31, 2011, 02:53 PM
Space Coast USA
hoppy's Avatar
Thread OP
Some pictures of the tail feathers.
A Hot Knife for making a slots in depron. It's a scalpel blade silver soldered to a piece of threaded brass. This was used to make the slot for the carbon fiber stiffener.
HK foam glue was squeezed into the slot and on the CF stiffener and then inserted into elevator.

Rudder has a 6x8mm balsa stiffener added.
Nov 07, 2011, 06:13 PM
Space Coast USA
hoppy's Avatar
Thread OP
Finished skinning the fuselage with white sandwich bag paper and polycrylic varnish. It added 20g of weight...not bad for a 30" long body IMO.

Also skinned the rudder and glued in the EPP landing gear support with gorilla glue and epoxied the plywood to the EPP. Glue tests with the epoxy showed the EPP ripped before the glue bond failed. The rudder was done with two pieces of paper, one that overlapped the edges and the other covered the opposite side and the overlapping tabs.
The wing templates have been made and cutting is next.
Nov 07, 2011, 06:16 PM
Space Coast USA
hoppy's Avatar
Thread OP
Finished skinning the fuselage with white sandwich bag paper and polycrylic varnish. It added 20g of weight...not bad for a 30" long body IMO.

Also skinned the rudder and glued in the EPP landing gear support with gorilla glue and epoxied the plywood to the EPP. Glue tests with the epoxy showed the EPP ripped before the glue bond failed. The EPP does a good job of absorbing those less than silky landing shocks.


The rudder was done with two pieces of paper, one that overlapped the edges and the other covered the opposite side and the overlapping tabs.
The wing templates have been made and cutting is next.
Nov 07, 2011, 08:50 PM
Registered User
yel914's Avatar
Nice project Hoppy. I'm a bit of a fan as I've built 2 of the 1/5th scale UPF-7s in the past few years. I'm just getting my feet wet in alternative building methods and I'm learning alot. Thanks for sharing your progress!
Nov 07, 2011, 10:38 PM
Space Coast USA
hoppy's Avatar
Thread OP
Thanks yel914, maybe you can help me....where is the cg on this plane?
Nov 09, 2011, 06:52 AM
Registered User
yel914's Avatar

Upf7 cg


Hoppy, I checked the CG on my UPF-7 plans last night. Wing chord on top wing is 11.75" and balance point is 2.125" from leading edge. The plans are for an Ikon N'Wst 1/5th scale so you're going to have to do a little math to scale down for your plane. I'll throw in a pic of one of mine to help spur you on! Hope this helps.
Rick -yel914
Nov 10, 2011, 02:34 PM
Space Coast USA
hoppy's Avatar
Thread OP
Some building techniques I use.
(Probably old hat to many but may be useful to those new to foam building.)

A Hot Wire band saw made from PVC pipe, a 2x4, 60# ss steel fishing leader and some eye bolts. This one runs on 5V.
Templates are made using Tile Print and glued to poster board with 3M77. Thumb tacks are used to pin the template to the foam.

The foam is covered with white paper bag material glued on with Miniwax Polycrylic.
A small brush with a shortened handle is left in the can to eliminate the constant cleaning. A coat of varnish is put on the foam, one side of the paper is coated and then placed on the foam. The outside is then coated with foam and a credit card is used to squeegee out the excess varnish.
Nov 15, 2011, 02:52 PM
Space Coast USA
hoppy's Avatar
Thread OP
The wing was built along the ideas presented by ExperimentalAir in this thread.
I've started with the lower right wing panel. It is made by folding Dollar Store ready board almost in 1/2 using a strip of 2" masking tape on the outside bend area along the crease line to keep it from splitting. The wing was then clamped in the folded position to 'permatize' the bend.
The hot wire band saw was used to cut the wing to shape.

The spar is 2 pieces of 2 1/4" wide $board separated by 2, 1/2" pieces of Depron with a channel for a 6mm carbon fiber spar. The separators were ended several inches from the end so the spar could be tapered to the wing tip. The outer 1/4 inch edge of the top and bottom sides was sanded to conform to the wing panel.

A piece of depron was added on the lower surface for supporting a servo and a 1/2" piece of $board was used as a secondary spar at the aileron edge to give a the wing a smoother shape rather than gluing it together at the aileron edge.

The wing is sort of symmetrical.

A new glue (for me), Aleens Fabric Fusion was used for everything except the secondary spar where I used Gorilla glue for it's expanding properties.
The Fabric Fusion (available at WalMart) is waterproof, strong and dries clear.

It's now clamped and curing.
Nov 18, 2011, 10:16 AM
Space Coast USA
hoppy's Avatar
Thread OP
Seems this is a real lonnnnnng project.
A couple pictures of a wing being made.
$board with 2" tape along outside of seam line.
Board lightly scored where it is to be creased.
Foam held in place with clamps and folded over.

Servo cutout procedure.
Template was made of servo outline.
Template taped to wing.
Foam cut with piece of music wire heated with a propane torch.
Neat flat with wing servo installation with wire running inside of wing to center exit hole.
Finally, the lower wing ready for final assembly.
Nov 19, 2011, 11:27 AM
Space Coast USA
hoppy's Avatar
Thread OP
The wing tip was finished and sanded.
With the LG attached.
Last edited by hoppy; Nov 19, 2011 at 11:33 AM.


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