My Hellcat, built for one purpose...

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My Hellcat, built for one purpose...

Postby Mitch » Wed Aug 20, 2014 11:29 am

Hello All,

Now that my Zero is finished as far as I can do aboard ship, I started on my 1000 series Hellcat. This Multi-Purpose kit would make a fine display, or big enough for RC, but I am attempting to build it to fly under the power of a rubber motor and hope to achieve at least a 20 second flight...

The planning room:
Image

The start:
Image
Get that tail lighter...

The build:
Image

...and the wing:
Image
...half the ribs, sanded, and lightened.

I plan to make the 5 not the 3. So the canopy gets chopped.
Image

The Fuselage has half the stringers, for now. I am lightening the frames, then I will add the rest of the stringers with contest balsa.
Image
...and that was done in 4 days at sea on our voyage from Dutch Harbor to Tacoma... more to follow.

I plan to cover the model with dark blue overall. I plan to use the kit prop for test flights, but this model could take a 12 inch prop!

Mitch

PS The plans say... for rubber power:
1. Sand the parts. Yes I did, and used less ribs, and cut away some wood, and used contest balsa in some places.
2. Do not use colored dope, one coat of clear dope. I will use Blue domestic tissue and lightly spray with dope.
3. Do not add any extra features that add weight. I will add only what is necessary to qualify for FAC rules.

I also plan to...
4. Add a little more dihedral.
5. Move the location of the rear peg forward one bay and use tan rubber.

I welcome any questions and comments... Keep Building, Keep Flying, Keep Learning! :D
Last edited by Mitch on Wed Aug 20, 2014 11:42 am, edited 1 time in total.
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Re: My Hellcat, built for one purpose...

Postby scigs30 » Wed Aug 20, 2014 11:37 am

Mitch, this is a nice build and this plane will fly with rubber no problem. This issue is not the balsa but all the plastic parts, so if you minimize the plastic it should keep the weight down. I would add all the fuselage stringers to prevent the starved look when covering. The fuselage is actually pretty light for a model this size, 1/16 vs 3/32. I am looking at starting the SBD Dauntless Guillows kit and it will be rubber.
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Re: My Hellcat, built for one purpose...

Postby Mitch » Wed Aug 20, 2014 11:48 am

Thanks for the comment. I will be adding all the stingers. For now it gives me room to get my dremel tool and x-acto knife. The fuselage is strong enough to handle now. I will trim down the fuselage frames. I plan to add the side louvers and steps but leave off all the bombs and such.

Image
Here is a picture of my 'ship board' work shop. The desk is metal so I use magnets, I also use a 2 foot balsa board for tail parts as I like to pin them down.
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Re: My Hellcat, built for one purpose...

Postby Mitch » Sun Aug 24, 2014 7:45 pm

Update from Anchorage, AK:

I painted the cowling 'Navy Blue' I have a nice 9 inch prop I got from the hobby shop that fits nicely:
Image

I put all the stringers in after I lightened the frames:
Image

And now I am ready to start assembling the wing:
Image

I decided not to use the kit wood for the LE. They seem very heavy and hard. I decided to use 2 x 1/4 square stock. They will also have a slight lap joint at each joint rather than a butt joint. I think the softer wood will be lighter and easier to cut down to shape. I was afraid of breaking my wing trying to cut down the hard 1/4 x 3/8 stock that came with the kit.

The TE E parts looked just a bit short so I cut my own and will use them in the center section you see. I will trim down the kit parts for the remainder of the TE.

The fuselage skeleton weighs 32g, The stabilizer is 5g and the Rudder is 2g...

back to my floating workshop... Mitch :D
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Re: My Hellcat, built for one purpose...

Postby davidchoate » Sun Aug 24, 2014 9:21 pm

Nice Mtch. I know that kit comes with all the bels and whistles, but if you omit them and build in your usual way, I make a prediction of youre AUW is going to be 84g's. (With Pilot). Remember I said that. If I'm right; My prize will be The Fly Gods allowing me a FF more than 3 sec. Just kiddin. I think David Lewis was right .He recommended some taile incidence. I think 2deg. or a 3/32" shim under the rear of the oriz stab.Will you be flying with the 9" 3blade, or that big black prop like comes with the Stearman.?
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Re: My Hellcat, built for one purpose...

Postby Mitch » Sun Aug 24, 2014 9:42 pm

Thanks for the vote of confidence... My guess is 120g... and I will try my best to get closer to the 100 mark. This is a big airplane, much larger than the nimble Zero. But with the large wing area, my ling loading should be in a good flying range. I plan to fly w/o the pilot... but I will paint up one and place him in the cockpit for a photo shoot. The Hellcat will only get the louvers, steps, and MG's...

I plan to fly it with the 10 inch 2 blade prop that comes with the kit. Bigger props are available. The 3 blade prop in the picture is designed for an electric motor, but will be on my plane for photo shoots.

Mitch
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Re: My Hellcat, built for one purpose...

Postby davidchoate » Sun Aug 24, 2014 10:35 pm

I tried 3 bladed props on electic motors with mixed results. I have found (the hard way) that the 3,and even 4 bladedprops work fantastic on small micro stuff, but on anything over80g's they just dont work as well as a 2 blade with a deeper pitch. I noticed that on the Air Core line of brushless planes,that they offer both 3,4,and 2 blade. The 3 and 4 being for scale looks, but switch to the 2 blade for performance. Go figure. I know on Gas engines the more bladed props add to performance. Maybe cause they have a much higher RPM's and less torque than electric. I remember 30yrs ago, my .049 Cox doin 17,000 RPM or somethin,and there was no throttle control. For its size,that little .049 Cox Tee Dee (they used a separate fuel tank for RC.) Pulling a 36" WS ,and heavy equipment as compared to today, no problem. It has to be the high RPM,and the electric having incredible torque, would be able to spin a deep pitch prop from idle with ease that would stall a glow engine. Thats what I think is goin on. If i'm right,then i'm starting to understand these planes finally. I'm sure Mr. Leis will know if I'm right. He is very helpful to me in getting these things flyable, much like Mr. Duckett was able to show Me how to make em look good. / I Love Zerosen404. My 2nd build,and even with some infilling, still on rubber, incredibly light for a 1:16. I have a FW190, and am scared of the same problem cause of the short nose. If I were to balance it for FF. it would weigh like 6 oz. at least. And I pirated the rubber from a 300 Dumas kit I got for my Bird Dog,and It's 30" ws aeronca, states AUW 62gm if built to plans,and wing area127 sq. in. It is not big or heavy, but has the big black 10" prop as my PT-17 Bipe. And what does FAI stand for. cause the rubber even feels different. The guillows rubber is harder. Guillows tells you to get FAI rubber from LHS to power their planes. Why dont they put it in kits. They are not exactly ElCheapo starter priced Novice kits anymore.I got alot of ideas for them, but I know they dont care. It took til2014 to ue LaserCuts ! Not that I care. I think its too easy.But atleast price em lower than Laser Cut Kits. I dont care bout a couple bucks,but whatabout the kid who needs 2 more bucks to get a Kit,and cant. He may've been the next Chuck Yaeger.
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Re: My Hellcat, built for one purpose...

Postby Mitch » Mon Aug 25, 2014 3:40 am

David,

I only plan to use the 3 blade prop for show. I bought is at a LHS on there parts board for flying models. I do not know what FAI stands for. I think Guillows puts the grey rubber in there kits because the kits built as per there instructions are heavy. So the grey rubber with more torque will get there plane in the air. I went though another learning curve when I shifted over to tan rubber, and changing props. Goes back to what I say... Guillow kits are Multi-Purpose kits. They are designed to be built in different ways and CAN fly on rubber. They are NOT designed to be specifically flown on rubber... IMO.

Mitch
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Re: My Hellcat, built for one purpose...

Postby Mitch » Fri Aug 29, 2014 3:36 am

Hello Guys and Gals and all Guillow Fans...

Home for a day and I have the skeleton finished:
Image
What you see weighs 102 grams... I think I will be approaching the 120 mark before I am ready to fly... we'll see.

All the little extra pieces on the tail added another gram to that. There were 8 more pieces to add a flair to the bottom of the rudder to match to the fuselage. The fuselage weighs 35 grams and the wing weighs 25. I don't think that is too bad for a model of this size and with the wing area I have.

I did not glue in the rear peg supports yet, but am planning on moving it forward one bay. (Where you see it now) I lightened the structure as much as I could or dared to do. I used some contest balsa for stringers and made the LE out of 2 laminated 1/4 inch stock. Other than that, the rest is all from the kit. I am not using the wing brace. I raised the dihedral 1/2 inch. It looks good and is still below the bottom of the cockpit (Maximum allowed in FAC rules) The wing is flexible but feels strong. I plan to add a little washout in the wingtips before covering. I plan to cover the model in the next few days.

There are a few more stringers that go in over the top of the rudder, and the bottom of the fuselage needs to be finished, but those go in after the model is assembled.

Mitch
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Re: My Hellcat, built for one purpose...

Postby David Lewis » Sat Sep 06, 2014 6:01 pm

FAI = Fédération Aéronautique Internationale, which makes rules for air sports competition events, both model and full size.

I believe Guillow's puts lower grade rubber and tissue in kits because most of them never get built and flown successfully, and the few that do get completed often end up as non-flying display models. Scarce and expensive contest grade material would be wasted or not appreciated by the majority of buyers.

Modelers who are willing to search and pay extra for FAI rubber are more likely building from plans or from scratch, not as much from mass produced, mid-market kits, compared to your average or casual model builders.

The 3 codependent variables that interact in longitudinal force arrangements are CG location, decalage and tail volume. As decalage increases, CG needs to move forward, you can get away with a smaller stabilizer, and L/D decreases.
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Re: My Hellcat, built for one purpose...

Postby DenisCullinan » Sat Oct 11, 2014 4:49 pm

[quote="Mitch"]Update from Anchorage, AK:

I painted the cowling 'Navy Blue' ................... Mitch :D[/quote]

Hello Mitch...

Can I ask what paint you used to paint the plastic cowling with?

Thanks,

...............Denis Cullinan
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Re: My Hellcat, built for one purpose...

Postby Brenda » Sat Oct 11, 2014 5:42 pm

That looks real good. What ship are you on that they allow building? On BB-61 they won't let me do anything like that.
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Re: My Hellcat, built for one purpose...

Postby Wildpig » Sat Oct 11, 2014 7:13 pm

Very nice build, Mitch.
I really like the looks of those ribs. Might save some weight, might not. But they just look cool. 8)
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Re: My Hellcat, built for one purpose...

Postby Wildpig » Sat Oct 11, 2014 7:22 pm

scigs30 wrote:Mitch, this is a nice build and this plane will fly with rubber no problem. This issue is not the balsa but all the plastic parts, so if you minimize the plastic it should keep the weight down. .....


I've heard that comment many times and got to wondering just what exactly are we dealing with.
From wikipedia I found that polystyrene plastic, I assume that is what's in the kit, weighs 1 gm/cc. According to an online conversion calculator that's a whopping 62 lbs/cu. ft. Who'da thunk that? :!: And you thought Guillow's wood was heavy. :wink:
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Re: My Hellcat, built for one purpose...

Postby Billy Mc » Sat Oct 11, 2014 8:53 pm

Brenda wrote:On BB-61 they won't let me do anything like that.


Wasn't the Iowa decommisioned and turned into a museum?
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