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Author Topic: fuel tank and set up for Hornet combat with OS 40  (Read 2118 times)

Offline Phil Goldberg

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fuel tank and set up for Hornet combat with OS 40
« on: January 06, 2018, 06:13:03 PM »
I am building a Pat King version of the Hornet combat ship.  My plans have no suggestion as to where to mount the tank or what kind of tank and size.  I am more familiar with Stunt planes.  The engine is a OS 40.  Any suggestions as to type of tank, size in oz.  and where to mount will be helpful.   Thanks,  Phil

Offline Steve Helmick

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Re: fuel tank and set up for Hornet combat with OS 40
« Reply #1 on: January 08, 2018, 12:13:18 AM »
Hornet was a Midwest kit with an upright engine, correct? I never had any of those, but the tank would be a Veco T-21 type, 1" tall square wedge. The way those worked out was that 3" long was 3 fluid oz, 4" long was 4 fluid oz. Strap it straight onto the top of the beams, but you might need to shim the tank or open it up and move the pickup to get equal revs in insides & outsides.

Tank size...um, well, if it's an FP .40 on suction, the tank might be nice at 3 oz for sport flying, but a .40H Pylon version might just burn a lot more. Are you planning to run uniflow, suction, muffler pressure, crankcase pressure? Pick your poison and post more information about your goals? Graffiti Combat, around here, guys use era correct engines and don't push them too hard. They also build and finish them to a much higher standard than back in the day.  D>K Steve   
"The United States has become a place where professional athletes and entertainers are mistaken for people of importance." - Robert Heinlein

In 1944 18-20 year old's stormed beaches, and parachuted behind enemy lines to almost certain death.  In 2015 18-20 year old's need safe zones so people don't hurt their feelings.

Offline Phil Goldberg

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Re: fuel tank and set up for Hornet combat with OS 40
« Reply #2 on: January 08, 2018, 10:52:50 AM »
Thanks for your reply.  The motor I plan to use is the OS FP 40.  Were the T-21 type tanks basically standard tank
pluming?  I ask because I have a 3oz standard Brodak tank laying around.  One concern that I have is that the engine seems heavy and I might wind up quite nose heavy without having to add a lot of tail weight.  Therefore I was considering putting the tank in the center wing further aft.  I was not wanting to add a muffler because of the extra weight and therefore would not be running pressure, however the tank position might be too low for the engine.  I am not sure how this works with an upright engine.  Another option is to use a bladder type fuel system in the wing but I would rather not have to go that route. 

Offline Al Ferraro

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Re: fuel tank and set up for Hornet combat with OS 40
« Reply #3 on: January 08, 2018, 08:29:39 PM »
I use pacifier pod behind a McCoy 35 Lightning Bolt engine. The pacifier pressure tank will gives more reliable runs, especially in turns compared to a hard tank. I would not add any tail weight till you fly the plane, Hornets are really hairy to get air born.
Al
https://stunthanger.com/smf/combat/hornet-combat-plans/msg470043/#msg470043

Offline Phil Goldberg

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Re: fuel tank and set up for Hornet combat with OS 40
« Reply #4 on: January 08, 2018, 08:34:46 PM »
I am not familiar with a pacifier pod.  Where can I acquire one?   Are these the same as bladders?   

Offline Dane Martin

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Re: fuel tank and set up for Hornet combat with OS 40
« Reply #5 on: January 08, 2018, 08:49:37 PM »
Try these. Otherwise we can recommend bladder sizes for days. I would recommend a bladder. It'll be a lot easier to set up.

https://m.ebay.com/itm/Combat-bladder-baby-pacifier-free-flight-pressure-fuel-system/172216355832?epid=1371059108&hash=item2818e50bf8:g:qfkAAOSwX~dWlFzN

Offline Al Ferraro

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Re: fuel tank and set up for Hornet combat with OS 40
« Reply #6 on: January 09, 2018, 08:35:39 PM »
I am not familiar with a pacifier pod.  Where can I acquire one?   Are these the same as bladders?   
You have to make it out of balsa wood, large enough it fit a hand ball inside, fuel proof the inside of it, and make sure there are no sharp edges that would puncture the pacifier when you fuel it. I use Gerber 76099 pacifiers on all my vintage combat planes. My Fox 36xBB needs a amazing amount of fuel to get it to run at its highest power level, and the pipette bulbs wouldn’t do the job.
Al
« Last Edit: January 09, 2018, 09:01:49 PM by Al Ferraro »

Offline Dennis Toth

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Re: fuel tank and set up for Hornet combat with OS 40
« Reply #7 on: January 10, 2018, 05:37:41 PM »
If you need 4oz what material do you recommend? Source?

Best,   DennisT

Offline jfv

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Re: fuel tank and set up for Hornet combat with OS 40
« Reply #8 on: January 10, 2018, 08:45:59 PM »
Here's a picture of the pod on Al's Hornet before it was painted.  Made from balsa and epoxy coated inside before it was glued in place over the original tank location.  Sealed all around the edges.  I also glassed it with 0.75 oz cloth on the outside.
Jim Vigani

Online Brad LaPointe

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Re: fuel tank and set up for Hornet combat with OS 40
« Reply #9 on: January 11, 2018, 07:23:08 AM »
The bladder tank will work much better than a hard tank . Since a lot of these classics only get flown once in a while a hard tank is always a pain to clean and maintain.

A rather novel idea a friend came up with was to use a brand new shiny metal tank for static display and a gutted plastic tank to replace it for a bladder compartment when flying . Since rubber bands were a very common method of tank attachment back in the day changing out the tank is a breeze. And period correct.

Brad

Offline Paul Smith

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Re: fuel tank and set up for Hornet combat with OS 40
« Reply #10 on: January 11, 2018, 07:28:10 AM »
Brad has a good point.

Back in the day, bladder pods were made with off-the-shelf plastic bottles rubber-banded on. 

So to be really authentic, find an empty 1960 vintage aspirin bottle.
Paul Smith

Offline Steve Helmick

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Re: fuel tank and set up for Hornet combat with OS 40
« Reply #11 on: January 11, 2018, 04:57:35 PM »
The OP needs to ask himself how fast he wants his combat-ish airplane to go. I'd guess it will be a sport model, and would expect the .40FP on suction would drag it to about 85 mph on 10% fuel and .015" lines (for solo flying only!) with some sort of APC prop...a 9-7 or 9-8 should do. Considering that our NW Sport Race Ringmasters and Shoestrings would make 75+ on a Fox .35 Stunt, also on suction (supposed to be stock, but some were and some weren't), it seems reasonable.

I'd wholeheartedly suggest getting a tongue muffler from RSM (they're really light an inexpensive) and that running the .40FP on a uniflow tin tank would work just fine for sport. If there's a desire to fly some sort of combat contest, the airplane isn't a good choice (for Speed Limit Combat) or the engine isn't the right choice (for Graffiti Combat). For sport flying, it'll do fine on uniflow.

Not sure what the "large" stock venturi is, but at combat-ish rpm's, up to a .312" bore will work with a .156" spraybar through it, and quite possibly with the smaller OS spraybar. I ran as big as a .312" on a K&B 4055, always on 10%, usually with an 11x5 Taipan in my Humongus. The engine ran fine, but didn't put out nearly as much suds as the .46LA, and was heavier by at least an ounce or two. I don't know where the OP flies, but we have only one site where mufflers aren't mandatory, and the days are limited on that one site. "Muffler up" and save a site!    y1  Steve
"The United States has become a place where professional athletes and entertainers are mistaken for people of importance." - Robert Heinlein

In 1944 18-20 year old's stormed beaches, and parachuted behind enemy lines to almost certain death.  In 2015 18-20 year old's need safe zones so people don't hurt their feelings.

Offline Phil Goldberg

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Re: fuel tank and set up for Hornet combat with OS 40
« Reply #12 on: January 19, 2018, 01:05:50 AM »
Steve, I am just going to use the plane for sport flying.  Although the small rudder is offset quite a bit would you recommend that I also, there is a little wiggle room,  canter the upright engine outward a little?   Phil


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