My big Hellcat
12-15-2001, 09:39 PM
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My big Hellcat
Hey warbird fans, attached is a pic of my Hellcat, and no, it’s not a Ziroli. It’s my own design. Sorry about all the different colors, but early on I was experimenting with different resins and testing compatibility before committing to the final lay-up. The fuse is dark green because I dyed the resin and put too much in. Oh well, that’s why they make paint. There’s a story behind this aircraft...... A few years back my brother and I were in the kit business selling P-38’s and this bird was going to be our third kit. We sold the business while this was still just a concept. Since my brother was the one who designed and flew the P-38, this was going to be one of my major contributions to the business. It always bothered me that I never finished the project and saw it fly. So, a while back, I finished the plug, made molds, laid up a fuse, and started building. It should be ready to fly in about a month. The wing spans 105 inches, and will be powered by a Quadra 100. This is the prototype, and will have plug in wings. The next one out of the molds will have a folding wing, and I incorporated the folding angle into the inboard wing section, which is integral with the fuse. With flaps and retracts it is expected to weigh about 45 lbs. I have Robart gear in this one but am having a custom set made by Sierra Precision which will go into the next (assuming this one flys well). The Robart gear is about 10% too small but it doesn’t sit too bad. Wheels are Glennis 6 ½ inch. The outboard wing panels are sheeted foam and plug in using aluminum spars and brackets, similar to those used in Byron kits. The foam wing panels were a major pain in the @#$% so the next will have a built up wing. If you have any question or comments just ‘fire away’
John Fangohr
John Fangohr
12-15-2001, 10:32 PM
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The molds
I made the plug from balsa and ply. Then laid up a five part mold from polyester resin. Extremely tedious process but the neat thing about it is, if I lawn dart it I can always lay up another and try again. I just hope the incidence angles that are built into the molds work out (stole them from the full scale). If interested, I could post a pic of one of the mold parts and explain how it was done.
John Fangohr
John Fangohr
12-15-2001, 10:55 PM
#5
My big Hellcat
If you don't mind please do.
I have always wanted to try and create a plug. Was considering ordering a foam cutter and making plugs from foam.
Also, let us know how you strengthened the fuselage with any formers or stringers etc....
Randy
I have always wanted to try and create a plug. Was considering ordering a foam cutter and making plugs from foam.
Also, let us know how you strengthened the fuselage with any formers or stringers etc....
Randy
12-16-2001, 01:29 AM
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Plug and molds
Here’s a pic of the plug and two of the mold parts. As mentioned earlier, the fuse plug was built using balsa and ply in the same way that you would build a typical kit. I started with a side view cut from 1/8 inch ply, cut my fuse formers down the middle and glued them to the ply profile. This was sheeted with balsa and when finished I flipped it over and repeated the process. I then covered it with fiberglass and started sanding, priming, sand some more, until you begin to think that you’ve lost your mind with what you have undertaken!
Once the fuse has a class A finish it’s time to plan the location of your parting seams, making sure that there will be no reverse curves which would make the mold parts impossible to remove. After several coats of wax and lots of planning, I took 1/8 inch ply, about 2 inches tall, and attached it to the plug, essentially surrounding what was to become the first mold part. A coat of PVA was applied, then 3 layers of resin and 6 oz. cloth (I used polyester because it was cheaper and I was more familiar with it. When that first lay-up cured, I brushed on a layer of very thick resin (pudding consistency) and covered it with ½ inch thick balsa blocks and when cured, covered that with another 2 coats of resin and cloth. The balsa blocks are a cheap and easy way to make the molds much thicker and very strong without having to lay up countless layers of cloth.
When the first mold part was cured, I removed the parting ply from where the next mold part would meet, took a ½ inch drill and bored small indentations into the resulting parting flange (these become alignment buttons for the mold that butts against it) and used the resulting surface to butt the next part.
Once the entire fuse was covered, it was time to say a prayer and hope that the parting preparation (wax and PVA was done correctly. Well, I lucked out and the molds came off.
Once you have the molds it’s a simple matter of laying up cloth and resin in each mold part, trimming it at just the right time <g>, then clamping all the mold parts together and joining the parts with fiberglass tape. Pop off the molds and you have a fuse.
Well, that’s the simplified version. In fact there were a few disasters along the way. There was a release problem with the first fuse I laid up because I didn’t know PVA had a shelf life. That first fuselage was almost completely fused to my molds! Took a month to fix them. Tried again and the next came out fine. I’m glad now that I didn’t put panel lines and rivets on the plug (too lazy at the time) because the molds would not have been repairable.
As far as formers go there are only two main formers running through the wing center section. To these attach the retract rails and the wing brackets. The remainder of the fuse is rigid enough not to need additional formers, with the exception of the tail where the hstabs and tail wheel attach.
If you need more info just let me know,
John Fangohr
Once the fuse has a class A finish it’s time to plan the location of your parting seams, making sure that there will be no reverse curves which would make the mold parts impossible to remove. After several coats of wax and lots of planning, I took 1/8 inch ply, about 2 inches tall, and attached it to the plug, essentially surrounding what was to become the first mold part. A coat of PVA was applied, then 3 layers of resin and 6 oz. cloth (I used polyester because it was cheaper and I was more familiar with it. When that first lay-up cured, I brushed on a layer of very thick resin (pudding consistency) and covered it with ½ inch thick balsa blocks and when cured, covered that with another 2 coats of resin and cloth. The balsa blocks are a cheap and easy way to make the molds much thicker and very strong without having to lay up countless layers of cloth.
When the first mold part was cured, I removed the parting ply from where the next mold part would meet, took a ½ inch drill and bored small indentations into the resulting parting flange (these become alignment buttons for the mold that butts against it) and used the resulting surface to butt the next part.
Once the entire fuse was covered, it was time to say a prayer and hope that the parting preparation (wax and PVA was done correctly. Well, I lucked out and the molds came off.
Once you have the molds it’s a simple matter of laying up cloth and resin in each mold part, trimming it at just the right time <g>, then clamping all the mold parts together and joining the parts with fiberglass tape. Pop off the molds and you have a fuse.
Well, that’s the simplified version. In fact there were a few disasters along the way. There was a release problem with the first fuse I laid up because I didn’t know PVA had a shelf life. That first fuselage was almost completely fused to my molds! Took a month to fix them. Tried again and the next came out fine. I’m glad now that I didn’t put panel lines and rivets on the plug (too lazy at the time) because the molds would not have been repairable.
As far as formers go there are only two main formers running through the wing center section. To these attach the retract rails and the wing brackets. The remainder of the fuse is rigid enough not to need additional formers, with the exception of the tail where the hstabs and tail wheel attach.
If you need more info just let me know,
John Fangohr
03-02-2002, 01:41 AM
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It Flew!!
Well, two weeks ago the aircraft made its maiden fllight. I haven't painted it yet because I wanted to see it fly before I went to all the trouble. Although the landing was a little touchy, it came home without a scratch. One of the ailerons came uncoupled near the end of the flight because I must have forgotten to tighten the screw securing the horn to the splined shaft. We noticed that it suddenly needed several more clicks of trim for no apparent reason. So it came in on one aileron and just a touch tail heavy.
It came out at 53 lbs, a little over what I had predicted, and it was decided that a few more pounds of nose weight are in order. So, it's going to be 55 lbs. before paint!
Am having a new muffler made, because the original broke apart during taxi tests, and we ended up flying it with that big Quadra exausting inside the cowl. It was a perfect day and I wasn't going to miss my chance to see it fly because of a muffler, so I took my chances and flew it anyway. Didn't hurt a thing.
Am attaching an 'at the field pic'
John
It came out at 53 lbs, a little over what I had predicted, and it was decided that a few more pounds of nose weight are in order. So, it's going to be 55 lbs. before paint!
Am having a new muffler made, because the original broke apart during taxi tests, and we ended up flying it with that big Quadra exausting inside the cowl. It was a perfect day and I wasn't going to miss my chance to see it fly because of a muffler, so I took my chances and flew it anyway. Didn't hurt a thing.
Am attaching an 'at the field pic'
John
03-02-2002, 01:49 AM
#11
My big Hellcat
Good Job!!!!!
The plane looks great, even unpainted. Besides when it's in the air it's hard to see those colors
Landing that beast with one aileron was a trick in itself. Keep us informed...
The plane looks great, even unpainted. Besides when it's in the air it's hard to see those colors
Landing that beast with one aileron was a trick in itself. Keep us informed...
03-02-2002, 03:51 AM
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Hellcat
John, put me down for a folding wing version ASP. And if you have any time left at the end of the day maybe you could do a 1/4 scale Staggerwing, a 1/3 scale GeeBeeZ, and maybe a Corsair ( folding wings of course). Seriously I would take any of the above!
03-02-2002, 03:56 AM
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Future kit?
I would first like to thank everyone for the encouraging replies and the interest in this becoming a kit. I’ve had a few local flyers ask me about this too. I guess my answer is, ‘It’s up to all of you!’ I suppose if there is enough interest I could do something with it. It needs a little refinement though. To begin with, it needs to be lighter. But that won’t be a problem because as crazy as this sounds I intentionally built this one heavy to challenge my flying skills and prepare myself for large scale jets. Although I’ve built and flown lots of big warbirds, nothing in the past comes close to the wing loading that this thing has. It doesn’t fly ‘heavy’ though, from what we could tell on the first flight. I need to redesign the wings too, as these are sheeted foam. The problem is that thick foam is hard to find and the cores needed to cut these were about 6 inches thick. A kit version would have built up balsa and ply outboard wing panels.
Another consideration would be the folding wings. As I mentioned in my first post this plane was intended to have folding wings. Although the real Hellcat had manual folding wings I was planning on motorizing them (like the Avenger) on the next one. Would you want the wing to fold? The angles are already molded into the fuse so it’s only a matter of engineering the mechanics.
Let me know what you think,
John Fangohr
Another consideration would be the folding wings. As I mentioned in my first post this plane was intended to have folding wings. Although the real Hellcat had manual folding wings I was planning on motorizing them (like the Avenger) on the next one. Would you want the wing to fold? The angles are already molded into the fuse so it’s only a matter of engineering the mechanics.
Let me know what you think,
John Fangohr
03-02-2002, 06:07 PM
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My big Hellcat
Hey John,
How much does that big Quadra weigh? That airplane just begs for a RCS-215 4-stroke gas radial from R/C Showcase!
What is your schedule for completing this project? Any chance of having it ready for the Extravaganza?
Sorry I missed its maiden flight! I can't think of a better test pilot than Lance... glad it came out ok! 70F in Febuary and I'm stuck doing things at home! Of course, this first March weekend I was supposed to be helping Dan clearcoat my P-47... and its a blizzard! Missouri weather... gotta love it!
Andy Steere
http://astro.umsystem.edu/andy/rc/
How much does that big Quadra weigh? That airplane just begs for a RCS-215 4-stroke gas radial from R/C Showcase!
What is your schedule for completing this project? Any chance of having it ready for the Extravaganza?
Sorry I missed its maiden flight! I can't think of a better test pilot than Lance... glad it came out ok! 70F in Febuary and I'm stuck doing things at home! Of course, this first March weekend I was supposed to be helping Dan clearcoat my P-47... and its a blizzard! Missouri weather... gotta love it!
Andy Steere
http://astro.umsystem.edu/andy/rc/
03-02-2002, 08:46 PM
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My big Hellcat
Sparky,
The three views that I used were taken from Volume 2 of the Scale Aircraft Drawings that are sold by Model Airplane News. All of the thrust angles, incidences, etc. were copied. Full scale has 3 degrees of down engine thrust so I have one degree in the firewall and two in the mount. Also added two degrees of right thrust.
Andy,
That Quadra weighs 10 lbs if I remember correctly. I looked at the engine that you mentioned and decided that it was a little too big (besides, if I remember correctly, it costs as much as a Buick). I won't take it to the extravaganza unless it's painted and I want to put a dozen flights on it before I strip it down. Will see how things work out with time and weather.
Yes, Lance is a great pilot. He hasn't flown many Warbirds though, and when it came time to land this one he chopped the power a little early. He was making a 50 ft. high, flat approach at low throttle with the flaps up (slow flight tests at high altitude indicated that stalls were gentle, slow, with only a slight drop of the nose and right wing). He cut the power about 75 ft. short of the runway and within a second, the tail started to drop and it began to wag its wings (stalling!!). I almost yelled in his ear "POWER, POWER" but he had already figured it out. A little power got the tail up and it over the runway, although it was still trying to stall a little during touchdown (came in on one aileron). Overall, he did a great job!!
Looking forward to seeing you P-47!
John
The three views that I used were taken from Volume 2 of the Scale Aircraft Drawings that are sold by Model Airplane News. All of the thrust angles, incidences, etc. were copied. Full scale has 3 degrees of down engine thrust so I have one degree in the firewall and two in the mount. Also added two degrees of right thrust.
Andy,
That Quadra weighs 10 lbs if I remember correctly. I looked at the engine that you mentioned and decided that it was a little too big (besides, if I remember correctly, it costs as much as a Buick). I won't take it to the extravaganza unless it's painted and I want to put a dozen flights on it before I strip it down. Will see how things work out with time and weather.
Yes, Lance is a great pilot. He hasn't flown many Warbirds though, and when it came time to land this one he chopped the power a little early. He was making a 50 ft. high, flat approach at low throttle with the flaps up (slow flight tests at high altitude indicated that stalls were gentle, slow, with only a slight drop of the nose and right wing). He cut the power about 75 ft. short of the runway and within a second, the tail started to drop and it began to wag its wings (stalling!!). I almost yelled in his ear "POWER, POWER" but he had already figured it out. A little power got the tail up and it over the runway, although it was still trying to stall a little during touchdown (came in on one aileron). Overall, he did a great job!!
Looking forward to seeing you P-47!
John
03-03-2002, 12:54 PM
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Do I know him?
Jimmy,
I do indeed know Dave Ragsdale. We've been friends for years. He called me the other night when he heard that my Hellcat had flown and wanted me to be sure and call him before the next flight.
Dave has some interesting projects underway, especially the big Brewster Buffalo, and I understand that he just acquired a B-17. I'm also well acquainted with the Ziroli Zero and Corsair that he flies because I built them both.
To elmshoot:
Forgot to mention in my reply above that the Hellcat is the dash 5.
John
I do indeed know Dave Ragsdale. We've been friends for years. He called me the other night when he heard that my Hellcat had flown and wanted me to be sure and call him before the next flight.
Dave has some interesting projects underway, especially the big Brewster Buffalo, and I understand that he just acquired a B-17. I'm also well acquainted with the Ziroli Zero and Corsair that he flies because I built them both.
To elmshoot:
Forgot to mention in my reply above that the Hellcat is the dash 5.
John
03-04-2002, 10:33 AM
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John;
Met you guys at the Ottumwa Fun Fly last year..I flew a Byron P-51..lost a wheel when the gear retracted for landing....Hopefully I'll bring my 'Tyhpoon"....Dave knows all about it..good luck with your "Hellcat"........Looks VERY good......
03-15-2002, 01:30 PM
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Hellcat... Would you considering selling kits?
Hi John, like everyone else I think your Hellcat is very impressive.
Based on the current flight tests do you think you will need to make modifications to the original design?
You mentioned in a previous discussion that you may consider producing the glass fuse for others. How many committed buyers, who are willing to pay in advance, would it take for you to start producing short kits.
Please let us know
Thanks
Norman
Based on the current flight tests do you think you will need to make modifications to the original design?
You mentioned in a previous discussion that you may consider producing the glass fuse for others. How many committed buyers, who are willing to pay in advance, would it take for you to start producing short kits.
Please let us know
Thanks
Norman