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Barry

F-4 Phantom Ejection Seat: Height Comparison

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In my bid to build a “more†accurate F-4 Phantom II cockpit than is currently available several interesting facts have come to light. The latest being that the Tamiya cockpit floor depth is too shallow by about 4 scale inches while the side consoles are correct; both with respect to the canopy sill. Out of that comes the issue that nearly all ejection seats available are sized to sit at the proper height when installed in the Tamiya cockpit and will sit too low in a cockpit with the correct floor depth.

 

So I dug out all of the Phantom ejection seats I have in my stash and here is what I have found.

 

Aires has an Mk 7 seat without harness in their F-4J cockpit set and available separately.

Quick Boost has the Aires Mk 7 seat with harness. Otherwise it is the same as the Aires seat.

Paragon has an Mk 7 seat that the height is sized to fit the Revell cockpit or a correct depth cockpit.

Reheat Models has an Mk 7 seat that like the Paragon is sized for the deeper cockpit floor.

Eduards Mk 7 seat appears to be better sized to fit the deeper cockpit but is “made†for the Tamiya kit.

Verlinden does an Mk 7 seat that is sized to fit the Tamiya cockpit.

TAC Scale Mk 7 sized to fit Tamiya

True Details has an Mk 7 seat that is sized to fit the Tamiya cockpit.

AMS Resin has an Mk 7 seat (USN/USMC and USAF versions) sized for the Tamiya cockpit.

AMS Resin has an H5 version also made for the Tamiya cockpit.

 

Other than Aires I have not included the seats that come in other AM cockpit sets as the cockpit except the Legend set are designed for the Tamiya kit so the seats are sized to fit them.

 

Here are photos for comparison; in the second “lineup†I have included the Tamiya seat. IMO it appears that the Paragon, Reheat and Eduards seats are better suited for the Revell cockpit or a scale depth cockpit while the others are best suited for the Tamiya cockpit.

 

Disclaimer; I make no attempt to extol the virtues of one over another only show the height differences.

 

Barry

 

P5170012_zpsuzol2d7s.jpg
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P5170040_zpslh8yttuz.jpg
P5170039_zpsysouivrb.jpg
P5170007_zpsqbg9suld.jpg
P5170006_zpsdznxiktq.jpg

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Nice comparison Barry. The MBA H-7 and Mk.7A ejection seats (and by extention, probably H-5 and Mk.5 seats as well, as the H-7 is a modified H-5 with rocket pack added) height is fixed by the overall length of the seat frame bulkhead mounted ejection gun (the upper drogue container and parachute pack support are pretty well fixed structures as they form part of the seat beam structure that slides up the gun rails). 

 

The lower seat pan can motor up or down within a typical range of five or six inches for individual aircrew height adjustment purposes, so this is possibly one reason why you get differing seat heights from various castings.

 

I will see if I can establish some key dimensions from an actual MBA Mk.7A-1 ejectionn seat for you.

 

Derek

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Barry, with a minus 4 scale inches being a difference between yours and theirs, what dimension strip applied to the bottom of the seat to bring the seat up to height would you recommend? Just curious.

 

Thank you.

Sincerely,

Mark

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Great comparison, Barry ... :goodjob:

 

One question springs to my mind when I see the line-up : how come the heights and widths can be so different (cockpit height considerations notwithstanding) for the same subject ? Does any one of the AM manufacturers work from actual measurements ?

 

Hubert

Edited by MostlyRacers

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Great comparison, Barry ... :goodjob:

 

One question springs to my mind when I see the line-up : how come the heights and widths can be so different (cockpit height considerations notwithstanding) for the same subject ? Does any one of the AM manufacturers work from actual measurements ?

 

Hubert

 

Hopefully, we will do soon... ;)

 

Derek

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I guess I have to revise my AM philosophy...To me, AM sets exist to add more detail (compared to the limitations of IM) and correct inaccuracies, so be a better representation of the scaled-down original, even if that implies ré working things like floor height.

 

Not a criticism of your approach, Harold, especially as you have demonstrated time and time again your commitment to getting things right. Just another epiphany for me, after discovering 40+ years ago that kits a) could be inaccurate, and B) could be corrected...mind you, some old experience with Verlinden sets should have forewarned me durably ...

 

Hubert

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I guess I have to revise my AM philosophy...To me, AM sets exist to add more detail (compared to the limitations of IM) and correct inaccuracies, so be a better representation of the scaled-down original, even if that implies ré working things like floor height.

 

Not a criticism of your approach, Harold, especially as you have demonstrated time and time again your commitment to getting things right. Just another epiphany for me, after discovering 40+ years ago that kits a) could be inaccurate, and B) could be corrected...mind you, some old experience with Verlinden sets should have forewarned me durably ...

 

Hubert

I am doing the same thing with the OV-10 seats. I was sent the measurements from an actual seat. I can only do as much to correct the out of proportion seat and still be able to fit the kit tub.

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Hubert,

 

The problem is bigger (no pun) than just boosting the height of the seat to use it in a “scale†depth cockpit. By reducing the length of the main beam the whole seat becomes “bunched up†in height. Harold's explanation sums it up. If you boost the height by shimming below the seat main beam then the bucket will sit too high.

 

Most of the seats would need a .100 to .125†shim to set the top of the main beam at the correct height with .125†being 4 scale inches in 1/32 if I have done my math correctly. :hmmm:

 

The reason the AM cockpit sets made for the Tamiya are shallow is to clear the nose wheel well. In fact I found that I could not lower the forward cockpit floor the full 4†without thinning the top of the nose wheel well until it was paper thin. Doing so weakens the mounting points for the nose gear strut to the point they will not hold the weight of the model. So the forward cockpit floor is only about 2.5-3†lower than the standard Tamiya floor height for pics of the problem see link.

http://forum.largescaleplanes.com/index.php?showtopic=56114&page=2

 

So the question becomes one of: why build a correct floor depth if the choice of seats that will fit is limited. The Paragon and Reheat seats I believe are OOP and the Eduards seats are the later H7 version. We would need an H5 seat for the early naval and land based versions. :shrug:

 

Barry

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Nice comparison Barry. The MBA H-7 and Mk.7A ejection seats (and by extention, probably H-5 and Mk.5 seats as well, as the H-7 is a modified H-5 with rocket pack added) height is fixed by the overall length of the seat frame bulkhead mounted ejection gun (the upper drogue container and parachute pack support are pretty well fixed structures as they form part of the seat beam structure that slides up the gun rails). 

 

The lower seat pan can motor up or down within a typical range of five or six inches for individual aircrew height adjustment purposes, so this is possibly one reason why you get differing seat heights from various castings.

 

I will see if I can establish some key dimensions from an actual MBA Mk.7A-1 ejectionn seat for you.

 

Derek

Derek,

 

Good information; I remember when working the Phantom that the Aft Ejection Seat had to be removed F.O.M. (Facilitate Other Maintenance) quite frequently. Removing any L.R.U. (Line Replaceable Unit) from the aft cockpit under console area necessitated the removal of either the Seat Pan (“Bucketâ€) or both the Bucket and Main Beam. There was more maintenance obviously required to remove both and the Egress Shop would challenge our need for both. For the most part we could get to most LRUs without removing the Main Beam. Removing the CADC (Central Air Data Computer) on the left aft side or the “Cuttler Hammer†Main Power Distribution/Control box on the right aft side usually necessitated the removal of both.

 

Harold has molded the Bucket and Main Beam as separate pieces for me using his seat as the master. I have every intention of modeling one Phantom with the seat or seats removed to show all that detail that is lost when the seats are installed. This would be one cockpit that I would want the proper floor depth and seat dimensions to be as accurate as possible.

 

It would be awesome to get actual measurements of the Main Beam O/A dimensions along with its primary components as well as those for the Bucket, (received your email).

 

Barry

Edited by Barry

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some modifications just arent necessary....   You have to remember scale modelling is about pulling off illusion of scale effect rather than trying to go millimeter for millimeter to shrink things....  some fixes are just a bad investment of time and resources....    4 scale inches of depth really only matter when it comes to shoing the profile of the seat over the side sills...

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some modifications just arent necessary....   You have to remember scale modelling is about pulling off illusion of scale effect rather than trying to go millimeter for millimeter to shrink things....  some fixes are just a bad investment of time and resources....    4 scale inches of depth really only matter when it comes to shoing the profile of the seat over the side sills...

That is one approach...IMO there is a difference in building a model of the subject and modeling the subject in scale. As for the effect of 4 scale inches in floor depth, everything that is mounted to the floor has to be adjusted in height to compensate for the 4 inches. But I can agree that without correct height seats it does seem a bit unnecessary.

 

Barry

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I'll let you in on a dirty little secret of the hobby biz:

 

Sometimes manufacturers of models, aftermarket bits, and even (gasp!) decals utilize the "TLAR" fudge it method.

 

Given that these are not miniature airplanes, but rather artistic sculptural representations of real airplanes, the TLAR method often works just fine.  Not that we don't and shouldn't strive to make them as "accurate" (whatever that means) as possible, but allowances have to be made.

Edited by Jennings Heilig

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I'll let you in on a dirty little secret of the hobby biz:

 

Sometimes manufacturers of models, aftermarket bits, and even (gasp!) decals utilize the "TLAR" fudge it method.

 

Given that these are not miniature airplanes, but rather artistic sculptural representations of real airplanes, the TLAR method often works just fine.  Not that we don't and shouldn't strive to make them as "accurate" (whatever that means) as possible, but allowances have to be made.

Agreed!

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