Yak-3M

[Clayton Magnet]

Does anyone have any specs on the new built Yak-3M fitted with an Allison V-1710? I assume that because they were intended for the private/airshow market, that they wouldn't be running at anywhere near the full capacity of the engine, and thus would not have any sort of maximum speed figures. As well, they would be using 100LL fuel as opposed to the 130 green gas from back in the day, which would limit the output.
This aircraft would have made an interesting what if scenario, If the Western allies had perhaps licensed built the Yak, and fitted it with an Allison or Merlin, and upgraded the somewhat crude construction.

 

[tomo pauk]

That would've been a some hot rod RAF could use it as a V1-catcher, USAF would've tried to get some extra range on it. Now that we're at it, perhaps it would be a good idea to purchase some Shvak cannons and have them installed in the wing roots, neither of the mentioned Western V12s don't allow firing through the prop (we'd discard the extension shaft V-1710 from here for obvious reasons).

 

[Shortround6]

Not only are the oil cooler intakes in the wing roots (although the ducts curve inward pretty quick) the wing roots also contain the wheel wells, and behind the wheels/landing gear are fuel tanks. Fuel tanks are also in the wing outboard of the landing gear.
One reason it is a hot rod is because it is small. With a wing smaller than Bf109 wing there is only so much stuff you can put in it.
Yak 3 (Yak1M?) held about 95 US gallons and the way the Russians flew them they had about 40 minutes of endurance on average missions. A slower cruise speed would obviously extend endurance/range.
Russian guns would have been almost mandatory if trying use an Allison (or Merlin) as the American .50 was over 20lbs heavier than the Russian 12.7mm. Since the 20mm ShVAK went about 88-90lbs roughly 1/2 the weight "saved" by not using a hub mount gin is used up by the heavier US guns. US guns also don't fire as fast. Two US .50s are hardly worth bothering with in 1943.
Two 20mm ShVAK cannon might be worthwhile armament. (same as LA-5)

 

[tomo pauk]

Perhaps my phrase 'wing roots' is a legacy of the stuff written about the Fw 190, that have had the inboard cannons with barrel going next to the main wheel when retracted; picture
With better part of cannons going there, the ammo boxes probably just outboard of them, the fuselage between the pilot and engine will be housing the fuel tank(s). Granted, with such a tiny fighter it would be tricky to house more fuel than it was done historically, and drop tanks won't make it a long range fighter.
On the other hand, the Yak 9D or DD with Merlin and drop tanks would've been a great asset for the Allied needs of 1943 and beyond.

 

[Clayton Magnet]

Perhaps two B-20 cannons mounted above the engine would fit, as they were no larger than the UB 12.7mm

 

[Shortround6]

Perhaps two B-20 cannons mounted above the engine would fit, as they were no larger than the UB 12.7mm

True but they don't show up until sometime in 1944 and even then it took quite a while to replace the ShVAK in many aircraft becasue it took a while for production to meet demand.

 

[tomo pauk]

The B-20 should fit - there was the Yak 3P (P = pushka = cannon) with two synchronised B-20s and third firing through the prop. Time-wise it is of course off for anything before late 1944.
The tables covering different Yak 3 models, from Stepanet's book, in Spanish, can be translated: link

 

[GregP]

I've never seen specs on the Yak-3M, but have seen specs on the Allison-powered Yak-9UM:
Empty weight: 1930 kg, Max 2800 kg, Allison with 8.8 supercharger, climb: 6000 ft / min, 370 mph @ S. L., 430 mph @ 18000 ft., Cruise 250mph.

Or so it is stated.

We have a Yak-3 with an Allison, but it is an original Yak-3 wing mated to a reproduction fuselage made here in California by a privately-contracted builder. As a Musem aircraft, we don't actually look for the maximum performance from the plane very often, and our Allison was a wee bit tired when it came out of our P-40. According to our pilots, it is a very fun ride, perhaps just a tad stiff on the controls at speed, but VERY maneuverable. But ... no numbers other than the fact that it CAN cruise at less than 50 gph fuel burn. Has no trouble keeping up with any formation of piston fighters flown whatsoever. Keep in mind they usually cruise at a comfortable power setting, but not really fast.

 

[Trilisser]

As well, they would be using 100LL fuel as opposed to the 130 green gas from back in the day, which would limit the output.

Not so. 100LL is designed to give the same anti-knock performance as the 100/130 fuel.

 

[bobbysocks]

I am wondering if this is the same kind of construction as the spitfire that a guy I know is building. it was plywood, balsa and a honeycomb material which what it is made out of escapes me ATM. he is also using the Allison engine. if that is what is going on with this yak it should be a rat raper as far as speed.

 

[CORSNING]

Hi Clayton, hope this helps some.
Bob Hannah Aviation Specs Yak-3
http://www.warbirddepot.com/aircraft_fighters_yak3-canu.1.asp

Sorry Clayton, I do not know what happened to the second entry. You
will have to go to google and type in: Warbird Depo-Fighters>Stephane
Canu's Yakovlev Yak-3.

 

[CORSNING]

Hi Tomo, always great to see your post.
I see Shortround6 is still keeping everyone in line with his great all around knowledge as
usual.

 

[GregP]

Hey Bobbysocks,

That is probably a Marcel Jurca Spitfire. We usually have one in our airshow built and flown by Bob Deford.

His is finished as a Mk V. It has 95% of the pertformance of a real Spitfire at less than 40% of the cost. Bob flies his rather conservatively since rebuilding an Allison isn't exactly cheap, but he still sees 300 mph on occasion and has no trouble staying with any of the warbirds. He typically cruise-climbs at some 2000 - 2500 fpm and stays at legal airspeeds. Below 10,000 feet, that's 250 knots in the U.S.A.. I believe he is flying a modified DC-3 prop and the Allison F-Series engine has 100-series internals, with 12-counterweight crankshaft and late parts rather than early parts in all places where they exist as early and late, like lifters, mags, etc.

Sometimes they go play in private airspace and get a bit livelier.

The Jurca Spits have wood wings, but are stressed to normal WWII fighter g-levels. You can tell them from the real Spits becasue the wings are smooth ... with no rivets. Otherwise it's hard to tell. Bob's has an original stick and rudder pedals from a Spitfire. The cockpit looks completely authentic aside from required modern radios and instruments. His Spitfire is like our museum birds in that it gets flown in severe clear weather .... no playing in the air on stormy days. These things take too long to build and/or repair for that crap! Wood wings and hailstones don't mix very well ...

 

[Shortround6]

This aircraft would have made an interesting what if scenario, If the Western allies had perhaps licensed built the Yak, and fitted it with an Allison or Merlin, and upgraded the somewhat crude construction.

The US and Britain weren't interested in aircraft like the Russians built. Part of it may be NIH, but the Russian aircraft couldn't do what the western allies wanted most of the time and tooling up for Russian style construction (set up plant for impregnating wood with phenol-formaldehyde resin, although the Americans used a similar process) or redesigning the structure to keep the external shape while altering the basic construction would take up too much time/effort for the results.
Russian construction, while crude at times, was also compounded by the lack of equipment. The YAK-3 in particular got some of it's light weight by by being under equipped even by Russian standards. Fewer than normal gyro flight instruments. One channel radio if it had a radio at all. Gas gauges were out on the wings and not in the cockpit. The pneumatic systems (landing gear/flaps/brakes) were very troublesome but lighter than hydraulic or electric. Perhaps the failure rate would not be acceptable to the Western Allies?

The Yak-3 was very good at what it did but the Western Allies wanted more general purpose aircraft or at least, aircraft that could be adapted to different roles with less trouble/effort than the Russian aircraft would need.

 

[spicmart]

That is one pretty bird. I wonder how it compares aerodynamically with the Me 109F, the cleanest of its breed.

 

[alejandro_]

Russian construction, while crude at times, was also compounded by the lack of equipment. The YAK-3 in particular got some of it's light weight

Apart from the low weight it had a very good surface finish. Hans-Werner Lerche, a Luftwaffe test pilot, flew one and he was impressed by the performance and wing surface finish. This meant that initially, the manufacturing time of a Yak-3 was ×2.5 greater than that of a Yak-9.

In late 1944 the British did consider asking the Soviet government to send samples of Yak-3, La-7 and TB-7/Pe-8. They were not really needed but they wanted to get something back for the Spitfires being sent to the USSR. It would also allow them to study Soviet engineering practices. There is no further mention so I assume it came to nothing.

 

[CORSNING]

The Yak-3 is good looking. I always considered the Yak-9U/P the best looking of the
breed though.

 

[bobbysocks]

Hey Bobbysocks,

That is probably a Marcel Jurca Spitfire. We usually have one in our airshow built and flown by Bob Deford.

His is finished as a Mk V. It has 95% of the pertformance of a real Spitfire at less than 40% of the cost. Bob flies his rather conservatively since rebuilding an Allison isn't exactly cheap, but he still sees 300 mph on occasion and has no trouble staying with any of the warbirds. He typically cruise-climbs at some 2000 - 2500 fpm and stays at legal airspeeds. Below 10,000 feet, that's 250 knots in the U.S.A.. I believe he is flying a modified DC-3 prop and the Allison F-Series engine has 100-series internals, with 12-counterweight crankshaft and late parts rather than early parts in all places where they exist as early and late, like lifters, mags, etc.

Sometimes they go play in private airspace and get a bit livelier.

The Jurca Spits have wood wings, but are stressed to normal WWII fighter g-levels. You can tell them from the real Spits becasue the wings are smooth ... with no rivets. Otherwise it's hard to tell. Bob's has an original stick and rudder pedals from a Spitfire. The cockpit looks completely authentic aside from required modern radios and instruments. His Spitfire is like our museum birds in that it gets flown in severe clear weather .... no playing in the air on stormy days. These things take too long to build and/or repair for that crap! Wood wings and hailstones don't mix very well ...

Could be Greg. I will have to ask him more about it when I see him or his son. I remember seeing a jurca mustang that used a ranger 6 cylinder engine back in the 70s....could never talk my dad into building it.

 

[GregP]

Bob flies his conservatively for the most part, being a retired airline captain. But he can mix it up pretty well when he gets the urge. His workmanship is outstanding. His Allison is a work of art, with hoses, cables and cables clean and polished. Everything is well-cared for, clean, and shiny ... pretty much all the time. Last time we look in his Cuno filter, even the screen was spotless!

 

[Trilisser]

The YAK-3 in particular got some of it's light weight by by being under equipped even by Russian standards. Fewer than normal gyro flight instruments. One channel radio if it had a radio at all. Gas gauges were out on the wings and not in the cockpit. The pneumatic systems (landing gear/flaps/brakes) were very troublesome but lighter than hydraulic or electric. Perhaps the failure rate would not be acceptable to the Western Allies?

Any evidence that the austere instrumentation was due to demand of light weight, not because of e.g. limited instrument industry? Or that being a short-range fighter, it did not need extensive instrumentation for blind-flying? As for the fuel gauges, didn't the Hs 129 have engine instruments on the inner side of the nacelles...

Any evidence that its pneumatic systems were troublesome due to being pneumatic? On the contrary, it is very likely that especially in winter conditions pneumatics are easier to maintain and more reliable too. And wasn't the very highly praised M. B. 5 also fully "pneumatic" for reliability and ease of maintenance...