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- Posted By: Jomo Stewart <Silo_FT@hotmail.com>
- Date: Monday, 10 September 2001, at 7:47 a.m.
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- Hello everyone.
- I was looking at some performance figures for the Ki-84-1a and notice
three number circulating.
- 388mph (as per Japanese tests on early production model)
- 422mph (TAIC from captured Ki-84 at Clark [92 octane])
- 427mph (at Wright field w/ rebuilt engine? [100 octane])
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- I have heard rumor that the orignal 388 number was done without using
water-meth injection, and the engine was run at 2900 RPM instead of the maximum
3000.
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- The 422 number was achieved with the water-meth injection and used
japanese 92 octane fuel.
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- Does anyone know the true performance of the Ki-84-1a... or rather the
most standard, using the common HA-45 21 engine?
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- Re: ki-84 performance...so which is it?
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- Posted By: Deniz Karacay <denizkaracay@yahoo.com>
- Date: Saturday, 15 September 2001, at 10:13 a.m.
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- In Response To: ki-84 performance...so which is it? (Jomo Stewart)
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- I talk from memory so I don't remember the designations but all above
might well be true. I don't think that any wartime Ki84 had capacity above
400mph unless, it was very well maintained.
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- Late Ki84s had upgraded engine of 1990hp as opposed to 1800hp (which
was hard to get anyway). I assume captured Ki84s were very well maintained and
serviced and they appear to be late models with more powerful engines. Lacking
paint also increase speed by several miles depending on paint.
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- If you look for Ki84s performance during war regarless of circumtances
take 380-390mph at most, usually it is even lower.
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-
British performance comparisons
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- Posted By: Graham Boak <graham@boak98.freeserve.co.uk>
- Date: Saturday, 22 September 2001, at 5:33 a.m.
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- In Response To: Re: ki-84 performance...so which is it? (Deniz Karacay)
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- In the latest Air Britain magazine Aeromilitaria there is a long
(half-page) column summarising the trials carried out using Seafires at Clark
Field from May 1945. There was to be a significant number of other US and
Japanese a/c in the trials, but because of various problems this was reduced to
the Frank.
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- Interesting comments include: the Frank was limited to 250mm manifold
pressure and 2900 rpm. It does not state why, nor how much of a limitation this
would have been.
- The Seafire could match aceleration at 5000ft, they climbed in
formation to 15000 ft, the Seafire then reached 20000ft 45 seconds before the
Frank. The rate of turn was tested at 5000ft between 160 and 180 knots
(presumably indicated not true). The Seafire outturned the Frank fairly easily,
combat flaps on the Frank not seeming to provide any improvement.
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- Frank's speed was 330mph at sealevel,
400mph at 20000ft. (with Ha 45 engine). Seafire pilots were advised to take
advantage of high speed performance superiority.
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- Frank was difficult to service, panels were not interchangeable and
difficult to fit. Poor rivetting, no protection against corossion. The
undercarriage was notoriously weak, difficult to maintain, tyres were difficult
to remove and the brakes incredibly bad. Pilot vision was poor.
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- Incidentally, the Seafire was judged superior to the F6F and P-51 below
10,000ft - no other information given in the brief article.
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- The source is ADM1/17474. Presumably there will be a similar report in
US archives?
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- Found it
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- Posted By: Deniz Karacay <denizkaracay@yahoo.com>
- Date: Monday, 24 September 2001, at 11:56 a.m.
-
- In Response To: British performance comparisons (Graham Boak)
-
- I have pic of NN610, Seafire MkIII with normal wingtips, flying
formation with a Ki84, F6F (look like F6F5 but quality and size of the picture
is poor, but can't see window behind pilot) and a P51D/K Mustang.
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- IJAAF tests during war shows Ki84 with Homare Ha45-11 of 1800hp did
388mph @ 19,685ft @ 8,576lbs and Ki84II with 1990hp Ha45-23 did 416mph @
8,495lb.
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- US test a/c did 427mph @ 20,000 ft but at
a much lower weight of 7,940lbs implying low fuel load and possibly without
ammo.
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- I am not surprised that Seafire III could out do most a/c at low
altitude, it was one of the best in that category.
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- Specifications come from Profile Publications #70, Nakajima Hayate Ki84
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- Re: British performance comparisons
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- Posted By: Jim Broshot
- Date: Saturday, 22 September 2001, at 6:29 a.m.
-
- In Response To: British performance comparisons (Graham Boak)
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- Does the article state which Mark(s) of Seafires were being used?
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- Re: British performance comparisons
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- Posted By: Graham Boak <graham@boak98.freeserve.co.uk>
- Date: Saturday, 22 September 2001, at 11:28 a.m.
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- In Response To: Re: British performance comparisons (Jim Broshot)
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- Not directly, but it does give the
serials of the two aircraft. NN610 and NN611. At that time and place they would
be L.Mk.IIIs. With the light weight and low-altitude rated engine that would
explain their performance: at higher altitudes the P-51D would be far superior.
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- OK,OK, I'll go and look for sure! Sturtivant's Aircraft of the FAA
confirms this, and names the pilot as Major P. Nelson-Gracie, Royal Marines.
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- There is a colour picture of an NN-serialed Seafire, with BPF
roundel/bar but no unit markings, at Clark Field in Jeffrey Ethell's Wings Of
War. I can't make out the rest of the serial but have no doubt it is one of the
two trial aircraft.
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- Re: British performance comparisons
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- Posted By: Jim Broshot
- Date: Saturday, 22 September 2001, at 5:41 p.m.
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- In Response To: Re: British performance comparisons (Graham Boak)
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- Confirmed by SUPERMARINE AIRCRAFT SINCE 1914 (Andrews and Morgan).
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- Seafire Mark III Type 358
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- "250, NN333 to 641, ordered 5 January, 1943, from Cunliffe-Owen
as: NN333-367, 379-418, 431-476, 488-528, 542-586, 599-641. Delivered as
LF.III."
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- Equipped with Merlin 55M with cropped supercharger impeller giving
1,585hp at 2,750ft.
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- Re: ki-84 performance...so which is it?
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- Posted By: Hiroyuki Takeuchi <hiryu@bigfoot.com>
- Date: Tuesday, 11 September 2001, at 1:37 a.m.
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- In Response To: ki-84 performance...so which is it? (Jomo Stewart)
-
- The Ha45 was designed to use 100 octane or at least 92 octane fuel but
most IJA fuel was around 87 octane and probably even worse towards the end of
the war. That means the motor had to be run on less boost and less power. Since
the engine quality and airframe finish were also suffering, that all reflected
upon performance. Writer Minoru Akimoto mentions that some Hayates in service
conditions were lucky to achieve 600km/h (370mph). No wonder the 580km/h
(360mph) Ki100 is often touted as the being better than the Ki84.
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- So while the Ki84 design had a 420mph potential, elements of reality
(poor fuel, faulty engines, rought airframe finish, etc) often limited its
performance to a lower level. May be the 624km/h (388mph) figure is about right
after all.
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- Re: ki-84 performance...so which is it?
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- Posted By: richard dunn <rdunn@rhsmith.umd.edu>
- Date: Monday, 10 September 2001, at 3:01 p.m.
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- In Response To: ki-84 performance...so which is it? (Jomo Stewart)
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- Don't know about "true" but
I'll give you what I found upon glancing at my files. A technical notebook
captured at Clark Field (ADVATIS No. 92) has rather complete data on the Ki 84,
however, it is undated and its source uncertain. Max speed is given as 624 kph
(=387.5 mph). This is at 6550 meters altitude, 2900 rpm and +250 boost. Fuel is
given as 92 octane and the capacity of the methanol tank is mentioned in the
report. Unfortunately another tech manual on the Ki 84 is published in
mimeographed form, completely sourced and dated, gives great technical detail,
but no performance data.
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- Two POW reports comment on Ki 84 performance. One POW (who flew the
Ki43-2) says max speed for the Ki 84 is 650kph true and 550 indicated at 5000
meters. Another POW, a Ki84 pilot, says max speed is 700kph true and 600
indicated. He gives no altitude and says he has never flown faster than 550 kph
indicated. Those speeds equate to about 404mph and 435mph respectively.
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- My impression (not just for the Ki 84) is that many Japanese fighter
pilots flew their aircraft in combat beyond "book" specifications and
got away with it.
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- Sorry, I can't answer your question with any certainty! The boost and
rpm data above may give some clue, though.
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- Re: ki-84 performance...so which is it?
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- Posted By: Jukka Juutinen
- Date: Tuesday, 11 September 2001, at 2:16 a.m.
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- In Response To: Re: ki-84 performance...so which is it? (richard dunn)
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- You mentioned boost of "+250". Is it in millimetres of
mercury? That seems as the only reasonable option. If it is, the boost is a bit
low for a max speed condition (about 40 inHg absolute). Or did the Japanese use
some different unit of pressure than any other?
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- Re: ki-84 performance...so which is it?
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- Posted By: richard dunn <rdunn@rhsmith.umd.edu>
- Date: Tuesday, 11 September 2001, at 6:36 a.m.
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- In Response To: Re: ki-84 performance...so which is it? (Jukka
Juutinen)
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- I have seen US translations of Japanese
documents equate +150 to 35.4 in. Hg and +200 equated to 37.8 in. Hg. So I
surmise that US technical personnel cosidered Japanese pressure measurements to
be in mm of mercury as you state.
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- As indicated in my comments above, I doubt Japanese pilots in combat
respected these numbers as limitations. In the Zero 21 +200 was take off power
and was not an authorized rated power otherwise. But this is also the
"overboost" power that we read about Sakai using so often in
"Samurai." Combat reports seem to indicate Zero pilots routinely used
this power in combat (smoke trails coming from Zeros in critical situations) and
I believe they used it for 10 minutes or more continuosly based on some
incidents I have read about. Their a/c were regulated not to exceed this boost.
Incidentally the Akutan Zero was tested at +150 and not +200 (engine ran rough
at 38" Hg and they were afraid of losing the aircraft).
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- POW reports indicate that while 92 octane was the standard fuel for
many fighter aircraft, they had 95 and 97 octane fuel as well. They also had
some captured 100 octane fuel early in the war (don't know if they produced any
later). The 87 octane fuel was authorized for use in high performance aircraft
only in transfer flights and the like at low rpm.
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- This is getting a bit off point but we may need to rely on general
background unless someone can come up with direct evidence.
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-
- Posted By: Kevin Hensel <hense@voicenet.com>
- Date: Thursday, 30 August 2001, at 3:15 p.m.
-
- I am currently building the 1/48 Hasegawa
Frank and am planning on using the Aeromaster markings for Corporal Takano of
the 57 Shinbu-Tai (white outlined red arrow running length of fuselage).
Aeromaster calls for the top surfaces to be painted black and the lower
surfaces IJAAF gray. However, theFAOW No. 19 has a Shigeru Nohara fold-out side
profile showing this aircraft in a very dark green over natural metal. My
instincts tell me that the dark green is more likely to be correct, although a
black Frank with red arrows would admittedly be an attention getter on the
shelf. Any ideas out there?
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- Re: Ki-84 color for 57 Shinbu-Tai
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- Posted By: Jay Carrell <carrell2@livingston.net>
- Date: Thursday, 6 September 2001, at 1:29 p.m.
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- In Response To: Ki-84 color for 57 Shinbu-Tai (Kevin Hensel)
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- I'm about to paint my Frank to go with the same markings.
- And I'm in the same quandry. Two days ago , I decided on a Scale Black
(w/ a little brown mixed in) over a gray underside. The upper color, who really
knows? The underside, I figure was probably gray because in my observations
most of the all NMF Franks, were NMF on top as well as bottom. And as I type
this, I'm vacillating back to the NMF lower which i think would make a sharper
looking model.
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- Re: Ki-84 color for 57 Shinbu-Tai
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- Posted By: Clark Hollis <chollis@stewart.com>
- Date: Thursday, 30 August 2001, at 4:14 p.m.
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- In Response To: Ki-84 color for 57 Shinbu-Tai (Kevin Hensel)
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- The exact color of that particular
aircraft will probably remain a mystery for all time. The uppersurface color
could have been dark green, dark brown, dark gray or black. It is a good guess
that the undersurface color was either natural metal or light gray. I'd be
inclined to use a very dark olive green on the uppers and a natural metal finish
on the unders, but I'm only guessing. You may find additional information,
which would help you, in the Faqs section of this board. Happy modeling
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-
- Posted By: Nelson R. S. Rapello <nelsonricard@ig.com.br>
- Date: Thursday, 15 March 2001, at 3:30 p.m.
-
- The Ki84 from the 22nd Hikô-Sentai,
pictured in the box art of the Hasegawa's 1/48(JT-67) Kit, has wing drop tank
installations represented under each wing. But examination of the Ki84's Model
Art #493, pages 17(Artwork) and 144(Photo), indicate to me that this aircraft
had a ventral drop tank installation, determining that it was a possible 2nd
increase prototype.
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- My questions are:
-
- 1-Can I think that, like others 2nd batch prototypes, this aircraft
don't had the wing's drop tank installations?
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- 2-Can I think that too, like many others prototypes this aircraft had
little doors(Model Art #493, Page 118 top photo), inclosing the landing gears
mechanisms (pages 103 and 104 drawings)in place of the bulges representeds in
the Hasegawa's kit?
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