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Old Sep 14, 2011, 01:28 PM
Aurora Builder
United States, MD, Lusby
Joined Nov 2003
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Interesting, I'm going to clean up some things on my tails, which in general I'm happy with (Edge vertical, Freaking Horizontal). These foils and similar plan forms are used on another molded plane that had similar response characteristics to my aircraft, but the tails can definitely have an effect (as proven by the popularity of Swindell's tails).

I think a large effect can be had by the leading edge shape, yours is likely near perfect, mine is not as I haven't used check templates and the bondo procedure outlined by Phil and Gerald on this wing.
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Old Sep 14, 2011, 01:47 PM
G_T
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Joined Apr 2009
5,715 Posts
There are subtle differences in the wings as well. A mouldie design allows a little more freedom in what one can do...

Gerald
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Old Sep 14, 2011, 02:33 PM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
USA, OH, Worthington
Joined May 2002
6,679 Posts
My leading edges are far from perfect and have gotten alot of my attention lately. I understand what you mean about molded LEs being much more repeatable, and I agree.
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Old Sep 14, 2011, 09:40 PM
But I am learning
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USA, MD, Cumberland
Joined Apr 2008
1,047 Posts
Tom I was impressed with the quality of the model I saw at the Bruce. I will have to ask for some stick time in Wilson. Please keep up the great work, we need a good plane to beat up on the Euro moldies.

Brian P.
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Old Sep 15, 2011, 05:48 AM
Aussie F3K Pilot
Melbourne, Australia
Joined Jun 2008
507 Posts
Awesome Tom

Tom,
As a felow molder of planes all I can say is great work and fantastic effort. They look awesome! It's also the greatest feeling when you put your heart and soul into a project and the end result flies so well. Well done!

We are about to start making molded Shark wings and I am interested in the layup you have decided on for these last few planes. I have molded a dozen F3B models (Carbon/Airex/Glass) but never a DLG wing. If you can help give us some pointers to get started then that would be great. From outside to inside..(by weight I mean gsm or oz/ft):
1. Any surface resin/thickener/finish?
2. Outer cloth weight?
3. Carbon Disser size (k) and spacing?
4. D Box Spread Tow Carbon weight?
5. Core material and weight?
6. Inner glass weight
7. Spar caps (tow/prepreg)?
8. Shear web?
9. TE web?
10. Hinge material/width?
11. L.E. of Ailerons?
12. L.E. of wing. Any reinforcement tow?
12. Root ribs/supports/reinforcements?
13. Joining spooge?
14. Spar caps layed into skins wet, then bagged?
15. Vacuum InHg?

Any other tips?

Thanks,
Marcus
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Old Sep 15, 2011, 06:14 AM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
USA, OH, Worthington
Joined May 2002
6,679 Posts
Marcus,

1. Any surface resin/thickener/finish?

Not on the surface. I use a foaming agent for the fillers and bog.

2. Outer cloth weight?

.73oz balanced glass on a bias

3. Carbon Disser size (k) and spacing?

1k carbon spaced 50mm

4. D Box Spread Tow Carbon weight?

80g/sm

5. Core material and weight?

Rohacell 31 IGF

6. Inner glass weight

.73oz balanced

7. Spar caps (tow/prepreg)?

4.1oz IM Uni carbon tapered from 15mm at root to 10mm at tip, probably overkill

8. Shear web?

100psi Dow Foamular 1000 machined to profile less 2.2mm for skins 12mm wide at root, 7mm at tip

9. TE web?

TE of wing is simply 6mm depron, no sock

10. Hinge material/width?

1.7 oz kevlar bias, roughly 10-15mm wide

11. L.E. of Ailerons?

LE of flapperon is 4mm depron with 1k carbon sock

12. L.E. of wing. Any reinforcement tow?

Nope, just spooge.

12. Root ribs/supports/reinforcements?

80g/sm spread tow root doubler as seen in pictures. Glass wings have a 3oz glass root doubler.

13. Joining spooge?

30g epoxy with 2 drops foaming agent, equal amounts of microballoons and cabosil

14. Spar caps layed into skins wet, then bagged?

Yep

15. Vacuum InHg?

All I can get from my 15 year old GAST pump... around 20in. I have a new pump that seems to do better but I'm not using it much due to the noise.

Other tips... tough one. With spread tow, the LE will get quite dry if you're doing everything right. I have used an epoxy roller on the mold to lay down a 10-15mm strip of epoxy at the LE and dusted it with cabosil before laying on the carbon. The epoxy causes the cabosil to stick, and the cabosil traps some extra epoxy there so that the surface is smoother when finished. If you're obsessive about LE quality (which I'm getting to be lately) then this helps a bunch.

Even though you may not really need it, use a 1k or 3k carbon sock over your shear web at the root that extends 8-10cm into each wing. This REALLY stiffens the root with only a 5-7g penalty. My wings are very thin so any extra stiffness I can get is welcome.

For the bolt locations, I 3m77 a couple layers of 6mm depron together and cut a thin U shape from that stock. It gets 3m77d to the skin at joining and makes a nice cup to hold the filler/hardpoint against the spar.

I don't shave or sand the rohacell, but rather I roll it after the whole assembly is in the bag. Use a hard roller and the edge of the resin channel as a guide, and just roll the taper into it at the TE. This mashes the foam and epoxy together, and the resulting TE is sharp and quite hard without any other reinforcement.

I 3m77 the inner skins to the rohacell prior to applying it to the outer skins in the mold. This just makes it easy to handle and ensures perfect alignment.

Skip the foaming agent when you mix the splooge for the LE. It causes small gas bubbles to get trapped in the resin and when you sand it, it exposes these bubbles. Just mix epoxy, microballoons, and a little cabosil for this.

Hopefully this all helps.
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Old Sep 15, 2011, 11:32 AM
Father of Fr3aK, DLG Pilot
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USA, OH, Worthington
Joined May 2002
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I had promised some pictures of tail setup etc. Here they are. Wire is .020 inch and there is roughly 2" betweem bends. New elevator has the hingeline running full span.

More coming of Ballast setup
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Old Sep 15, 2011, 03:50 PM
F3K
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China, Shanghai
Joined Feb 2007
67 Posts
Hi Tom,
Is that a two springs setup for the elevator?

Kelly
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Old Sep 15, 2011, 03:54 PM
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Reno Nevada
Joined Oct 2007
2,560 Posts
Tom,

How do you connect and disconnect the elevator pull string so you do not lose it down the tailboom when disconnected? I have been wondering how to do it. I assume the slot in the boom is reinforced also?

thanks,
Chris
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Old Sep 15, 2011, 04:03 PM
Registered User
United States, SC, Mt Pleasant
Joined Nov 2003
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Looks great Tom! I'd love to get my hand on one!

James
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Old Sep 15, 2011, 07:16 PM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
USA, OH, Worthington
Joined May 2002
6,679 Posts
Yes two springs on the elevator (and rudder when I occasionally use one)

The disconnect is via a slot in the control horn. The string has a loop tied and CA'd at the end.

James, coming to the ECHGLF? I saw in another thread that they had a going "South" party for you in WA. Come find me and you can give one a spin.
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Old Sep 15, 2011, 07:57 PM
Aussie F3K Pilot
Melbourne, Australia
Joined Jun 2008
507 Posts
Thank you Tom

Hi Tom,
That is a great list of information - thank you! It really helps.

After building F3B models it is going to be psychologically difficult to put foam in as the shear web (Arghhh!!) and Depron (OMG it has no strength!!!) as the TE spar. I can do it...I will..I promise...I can!!!! LOL

One bit of info I can help you with is that I got an improved surface finish by reducing the vacuum presure. I use 10in. It reduces the print through pattern of the glass or rohacell on the finished wing and the bond strength is still excellent.

Thanks again for all the good info and I hope you kick a@$ss with your plane.

Cheers,
Marcus
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Old Sep 15, 2011, 10:29 PM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
USA, OH, Worthington
Joined May 2002
6,679 Posts
Thanks Marcus. Since I debulk before the main bagging, maybe I'll give that a fling.

Tom
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Old Sep 23, 2011, 10:10 PM
Father of Fr3aK, DLG Pilot
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USA, OH, Worthington
Joined May 2002
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So after quite a bit of thought and a couple of discussions with my wife, I am going to do a limited production run on this airplane. Read on if you're interested.

Here's what will be included:

One piece bladder molded 2.4 friendly fuselage. The fuselage is designed for one or two JR DS-188 or similar servos with pull/spring controls. It's roomy enough for radio gear but still remains slim to keep drag to a minimum. Wing mounting hole locations are marked in the mold but are not drilled. Typical weight 40-45g with canopy and tail mount.

One piece molded Spread Tow / Disser wing, predrilled for wing attachment at the hardpoints. The wing is too thin to mold in the servos and do RDS, so plan on cutting the servo holes out and doing top drive. Hyperion DS09s and Airtronics 802s will barely fit but anything thicker should be avoided. The wing is strong enough for even the most brutal launchers among us and the torsional stiffness has been described as "overachieving." Typical weight 130-140g before servos.

Molded tail surfaces, either with or without a rudder. These are stronger and stiffer than most on the market, built at 15g per set typical. The horizontal is designed as a hinged stab, but I can accomodate a full flying version if you'd prefer. The hinged horizontal is predrilled and countersunk.

Horizontal stabilizer mount, predrilled and tapped.

Hardware kit including throwing peg, control horns for top drive and tail surfaces, springs, strings, spring carriers (aluminum micro tubing,) wing bolts and threaded metal inserts, tail bolts, canopy attachment rod, and setup instructions.

Here's how this will work: I will be doing a limited production run of 10 kits for starters. I have all of the materials for this amount of work on hand, and I will likely begin production in about 3 weeks. The first kits should be available in early November. If you'd like to get on "the list" for these, please send an email (not a PM please) to my screenname at Gmail. Please include your name, address, phone number, email, right or left handed, rudder or rudderless preference, and whether you wish to remain "anonymous" on the list. I will be hosting a website detailing production and the list will be published there, along with anticipated completion dates. Since this project is fully rooted in the USA, my initial production will only be available here. I expect to be able to produce three or four kits per month initially, with hopes to get more production as time goes on.

Keep in mind please that these are being built by me, in my house, in my spare time... and the quality has been increasing steadily but in my opinion, the fit and finish is not to the level of the Stobel / Steigeisen / Blaster just yet. With that thought, I'll initially be offering these at $700 USD plus shipping, due when it ships. If you get on the list and your kit is complete, you'll receive a call and / or an email from me requesting payment. At that time you can either pay and I'll ship, or you can decline and I'll offer it to the next person on the list.

I have had several requests from people to be on this list in the past, and if you're one of those people, please send me your information anyhow and you'll be given preference. I know who you are. Everyone else will be treated as first come / first served. The list will be published toward the end of next week with some rough target dates attached.

This is a very exciting time for me, completing the project... but also very scary in committing the time to build for others. I'm glad though to give a molded DLG option for people who wish to buy products made here in the USA. With a bit of prodding, maybe we can get more folks here producing parts or airframes.
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Old Sep 23, 2011, 11:01 PM
Jim C
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1,473 Posts
Tom, I am excited for you and those of us in the USA to see this exciting venture reach the next stage! Best wishes. Did I say I am excited?
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