Chris Z

My Feedback: (24)

I'd like to see what how you hotspot guys are mounting the wing-fin-to the fuse on the Hotspot???
Pictures would be great.
Thanks,
Chris

Woketman

My Feedback: (6)

Chris, I don't have any photos, but I just epoxied a 1/4" piece of ply into the fuse near the trailing edge (but where it was still thick enough). I then drilled & tapped it for a #10 bolt (I think). Then I roughed up the joining surfaces and cleaned them well, put lots of slow dry epoxy on them and epoxied the verticals onto the fuselage and used the bolts to mash them down real good. Might be over kill, but I could not forget all of the rumors about verticals fluttering and this lets me sleep at night. Take care.

Chris Z

My Feedback: (24)

woketman, thanks but I want to keep the fin and wing removable for transporting.
You brought up a good point with the fin fluttering, did you use any carbon fiber for stiffening?

Woketman

My Feedback: (6)

Yes, I did. I laminated a piece of unidirectional carbon on both the outboard and inboard sides of both verticals. The strips were each about 4.5 to 5 inches wide. It was overkill however, because the primary area of flexibility is still the fuselage right at the vertical/fuse joint. It seems that the fuselage is so shallow there that the couple that reacts the Mx moment is too close together. So don't go as overboard as I did with the carbon fiber as you will still have the flexibility of the fuselage. But the good news is that mine has held together very well with no flutter issues. I will have it at Fla Jets, if ya wanna see.

Chris Z

My Feedback: (24)

Where did you get the carbon fiber? And yes, I'd like to check out your jet at FJ.
Chris

jason

My Feedback: (1)

I don't know what kit you are using over there in the states, mine is the graupner one which has a alloy tube glued at a angle in the top of the wing and coming out mid point between the top and bottom and front to back of the wing root, you then glue a drilled dowel in the alloy tube and screw a 5mm cap head bolt through the top of the wing, fin and fus root into a captive nut glued inside the fus to a piece of ply when tightened up it sandwiches the fin between the wing and the fus. My fins are glassed with 2oz cloth for strenth and then profilmed. It's had many flights with the jetcat P120 and never a flutter


good luck

jason

Woketman

My Feedback: (6)

I got just enough from Eddie to do the job. I've got lots of bi-directional carbon that I'll cut you a piece of, if you can give me exact dimensions you need, but I did not want to add the extra weight and Eddie had uni. I think he got it from Aircraft Spruce and Scecialty, or what ever they are called. It ain't cheap though.

Jetman007

My Feedback: (6)

We have uni-directional cf cloth in stock. It's 12" wide and sold by the foot of length for $5.50/foot.

We recommend using a high strength epoxy (WEST Systems) to adhere it to your fins.

GeorgeR

My Feedback: (2)

Hi,

Best method is to glass the using 2oz cloth with uni-directional carbon fiber below. This yields a very light and very stiff fin. On my Hotspot I used 5 inch wide 3.5 oz weight uni-directional carbon called uni-web on both sides, available from aerospace composites. I vaccum bagged the whole thing then bolted the fins to the fuselage via hardwood blocks that I glued in. Depending on the attachment method of the wing this may or may not be necessary.

Good luck.

George R.

Woketman

My Feedback: (6)

Chris, I did essentially what George did, except I only bagged the uni-carbon and I put much more on it. What Gearge did is more reasonable than what I did (or over-did ).

Chris Z

My Feedback: (24)

Thanks guys,
I finished one wing last night and it fits great.
I always wanted to get into vacum bagging systems. Where can I get a relitivly inexpensive vacume system?
Vaccume bagging seems to be the way to go!

Woketman

My Feedback: (6)

Not only is bagging the way to go, but its down right clean fun. Its Christmas morning, all over again, every time I go out into the shop to take the bag off! I use a vac pump that is just a compressor from a trashed fridge. Just gotta remember to dump some oil in it every time I use it. I use big trash bags as vac bags and seal the edges with duct tape. Works great every time. The only commercial thing that I use is peel ply. I put a couple of layers of paper towel on the outside of the peel ply to soak up the extra resin. I learned most of this from Eddie.

Chris Z

My Feedback: (24)

Sounds easy, where do I get the peel ply?

Woketman

My Feedback: (6)

These guys have it http://www.aircraftspruce.com/main.html and I'm pretty sure that Art does too http://www.arts-hobby.com/index_mod.htm

Chris Z

My Feedback: (24)

Woketman thanks,
I'm compiling a list for Art. I should be all set, can't wait to see your Hotspot!
Chris

Woketman

My Feedback: (6)

Don't get too excited, its not much to look at. My beautiful wife gave it to me for a Father's Day present last year. What a sweetie! I built it real quick just to have something to fly while building my next Isobar. As such, I did not spend a great deal of time painting and just grabbed a few cans of Krylon from Walmart. It looks like hell, but its quick & cheap!

Chris Z

My Feedback: (24)

Hey,
don't worry, been there and done that. It's nice sometimes to have a not so pretty flying machine that's fun and reliable!
While I have you online, I'm assuming that you lay the peel ply on last, vaccume bag it and then peel the ply off ( After curing) leaving an smooth finish?
So which peel ply are you using, the 1.8 oz or the 2.7 oz, does it matter or do the oz difference effect the finish?

Woketman

My Feedback: (6)

That is exactly what my Hot Spot was built as - a fun reliable beast to fly. Well, the way I did it, with the rather coarse uni-carbon that I used, the finish was determined by the fact that the carbon produces ridges. This was then, somewhat, mitigated by the fact that I put a fine weave (do not remember the weight) glass cloth over it. I could have filled and sanded, ya da ya da, and gotten a perfect finish, but that was not my goal here. Anyway, I simply applied the carbon to the wood, soaked in the resin, applied the peel ply, then paper towels on top, put it all in the bag and let her rip (so the towels are last, against the plastic bag)! I could have done, like George did, the glass step at the same time, but I did not. As for which weight of peel ply, I have zero Idea what I have. I bought it years back. I'd just get the light stuff and you should have a finer weave pattern left after, if you can see it ay all. Please let me know how all of this goes for you, after all, us Lockheed Martin guys have to stick together against the Evil Empire! Be sure to practice first on some test pieces.

Chris Z

My Feedback: (24)

Thanks again,
hey did you see our stock yesterday! We closed at 51.00. If this keeps up, I'll be buying BVM.
See you at FJ's.

patf

My Feedback: (4)

Chris,

Aerospace composite had a low end vac bag kit that was under $100. had all the starter stuff, bag peel ply, etc. their epoxy was really nice as well.

Pat F
Austin