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Author Topic: Palmer type tank  (Read 1137 times)

Offline Michael Millard

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Palmer type tank
« on: July 12, 2021, 04:07:17 PM »
 I have a set of plans for an Aussie Spitfire VIII(Pentland) that calls for a Palmer type tank. What is it, and does anyone make them.

Offline Dave Hull

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Re: Palmer type tank
« Reply #1 on: July 13, 2021, 12:35:34 AM »
Hmmm. There is an Aldrich-style tank but never heard of a Palmer-style tank. I'd be curious to know what it looks like.


Offline Dave_Trible

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Re: Palmer type tank
« Reply #2 on: July 13, 2021, 05:17:38 AM »
Like the others, I am unaware of a Bob Palmer style tank. His designs were mostly kitted by Veco and called out Veco tanks so maybe that is what was meant.  However if you don't want to build a tank you can order one from Brodak.  I'd suggest it be uniflow and there is a good selection of sizes.  I make my own but was just looking to find one that was a match for the Veco T21C (i thought they made some copies of the Veco tanks-guess not) but nonetheless you should find one to fit your airplane.

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« Last Edit: July 13, 2021, 05:50:13 AM by Dave_Trible »
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Online Dallas Hanna

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Re: Palmer type tank
« Reply #3 on: July 13, 2021, 05:26:13 AM »
Hmmm. There is an Aldrich-style tank but never heard of a Palmer-style tank. I'd be curious to know what it looks like.

From Ron Moulton's (U.K) Control line Manual early 1960s.

Offline Dennis Toth

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Re: Palmer type tank
« Reply #4 on: July 13, 2021, 06:33:28 AM »
Dallas,
Thanks for posting the tank drawings. The drawing of the Palmer tank looks like a uniflow with the uniflow line near the front, but it doesn't indicate if the vent is cap for flight. Does the Ron Moulton's (U.K) Control line Manual give any additional information about capping the vent?

Best,   DennisT

Offline Dan McEntee

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Re: Palmer type tank
« Reply #5 on: July 13, 2021, 03:33:10 PM »
  Look at that Palmer tank closely. It is sort of like a speed model coffin tank. It is wider at the front that it is at the back, The pick up tube only goes back about 2//3 of the way, and then the baffle. The baffle has the point snipped off so fuel can pass through to the pick up. The "filler pipe" goes into the tank at the front and ends in line with the pick up tube, and could act like a uniflow as we know it today. It should be left open to atmosphere or muffler pressure. The "vent tube" is the over flow and should be plugged off in my opinion, but if you build it you may need to experiment with that. Centrifugal force will make the fuel load travel forward up the incline in the tank towards the front. It looks like a difficult tank to build. Of the two presented, I would build a uniflow version of the Aldrich tank. Just make sure your capacity is adequate for what you need.
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Offline ericrule

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Re: Palmer type tank
« Reply #6 on: July 13, 2021, 04:45:47 PM »
Mr. Palmer worked for Veco so what you are looking for is a Veco tank 2" wide x 1" thick with a "V" shape on the outboard thickness. The length of the tank determined the volume as that style of tank is 1 oz of fuel per inch of length. RSM Distribution sells this style of tank in both standard vent and uniflow. Check out the web site and you will see pictures of the tanks.

Offline Dan McEntee

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Re: Palmer type tank
« Reply #7 on: July 13, 2021, 05:10:17 PM »
Mr. Palmer worked for Veco so what you are looking for is a Veco tank 2" wide x 1" thick with a "V" shape on the outboard thickness. The length of the tank determined the volume as that style of tank is 1 oz of fuel per inch of length. RSM Distribution sells this style of tank in both standard vent and uniflow. Check out the web site and you will see pictures of the tanks.

      Look at the front and rear dimensions. It's 2" wide at the front and 1 3/4" wide at the rear. It may have been a production tank for VECO. I think VECO even had a version of a clunk tank with the clunk being a solid tube that pivoted around the pick up tube to tope and bottom. I think I have seen a similar drawing of it some where. I don't think it's worth the effort. Baffles have been proven to be of no effect and useless, the construction looks difficult and troublesome. A standard production uniflow tank or a properly plumbed plastic tank is cheaper and easier to trouble shoot.
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Online Dallas Hanna

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Re: Palmer type tank
« Reply #8 on: July 13, 2021, 05:33:18 PM »
      Look at the front and rear dimensions. It's 2" wide at the front and 1 3/4" wide at the rear. It may have been a production tank for VECO. I think VECO even had a version of a clunk tank with the clunk being a solid tube that pivoted around the pick up tube to tope and bottom. I think I have seen a similar drawing of it some where. I don't think it's worth the effort. Baffles have been proven to be of no effect and useless, the construction looks difficult and troublesome. A standard production uniflow tank or a properly plumbed plastic tank is cheaper and easier to trouble shoot.
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Dan, the 1 3/4" is the width of the flat making the width of the "V" 1/4" giving a total of 2" parallel.

Online Dallas Hanna

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Re: Palmer type tank
« Reply #9 on: July 13, 2021, 06:26:05 PM »
Dallas,
Thanks for posting the tank drawings. The drawing of the Palmer tank looks like a uniflow with the uniflow line near the front, but it doesn't indicate if the vent is cap for flight. Does the Ron Moulton's (U.K) Control line Manual give any additional information about capping the vent?

Best,   DennisT

Dennis, I can't see any mention of the overflow being blocked in Moulton's text but it does on the Skyscraper plan.  No doubt Bob had uneven running upright/inverted and resorted to raising the uniflow pipe to the top of the tank.  Also note that the feed pipe is now past the baffle whereas the drawing in Moulton book says feed pipe stops short of the baffle.  As others have said, the baffle not needed.

D

Offline Dennis Toth

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Re: Palmer type tank
« Reply #10 on: July 13, 2021, 07:22:01 PM »
I'm not sure when the current version of the uniflow tank came about, but the way it was used in the Skyscraper would have the tank pressure reference point is all wrong. But because of the caps at the top of the tank maybe it doesn't work as a uniflow.

Best,   DennisT 

Offline John Park

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Re: Palmer type tank
« Reply #11 on: July 14, 2021, 04:43:31 AM »
It seems that Ron Moulton, along with a lot of other British fliers, didn't understand the principle of the Uniflo tank for quite a long time.  I didn't learn of it (the 'Mariotte bottle' principle, as physicists call it) until about 1967, when I was having continual trouble with my diesel-powered aerobatic models going lean as the tank emptied.  I modified one of my tanks with a new filler pipe that ran straight across to the wedge (at the front, not angled back), and arranged to plug the overflow vent for flight.  The resulting engine run was a complete transformation, and all my subsequent tanks have been Uniflo: the early ones were Palmer-style, with a baffle, but I found them fiddly to construct and noticed no difference between them and the simpler versions.  I did once try flying with the overflow vent left open, just to prove to myself that it had to be plugged, and the flight (incredibly rich to start with, leaning-out progressively as the tank emptied) left me in no doubt.
I think Bob Palmer may have believed his 4-2-4 stroke 'switching' run had something to do with variation in fuel delivery during the manoeuvres, and perhaps he reckoned the baffle, and the positioning of the fuel pick-up, was beneficial in some way.
By the way, Ron Moulton knew of, and some people used, the 'chicken hopper' principle from as early as the 1950s, to give a constant mixture strength in team racers.  'Chicken hopper' and 'Uniflo' tanks are, of course, based on exactly the same general principle.
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Offline Steve Helmick

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Re: Palmer type tank
« Reply #12 on: July 18, 2021, 07:18:15 PM »
I'm not sure when the current version of the uniflow tank came about, but the way it was used in the Skyscraper would have the tank pressure reference point is all wrong. But because of the caps at the top of the tank maybe it doesn't work as a uniflow.

Best,   DennisT

I'd agree with DennisT on this point. The only other explaination is that Palmer didn't draw the tank and the person who did was incorrect in their understanding of what Mr. Palmer described. Stuff seemed to happen like that quite often.  y1 Steve
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