Just out of curiosity - Airplane Guys

Stupid questions for airplane people. Counter-rotating prop questions (I was looking at Tu95).
In ideal configuration>
1) do the axial rotation of outer prop and inner prop rotate at the same revs?
2) if they do, what is the (ideal) phase relationship?
3) what is the reality on Tu95 according to the above.

Helios with coaxial rotors>
same question series. 1,2,3

My WAG> fwiw the Tu seems to my eye to "answer" 1 > yes 2> there's maybe 5 or 10 degrees of phase shift.

as to helios, I have no real idea...

What say the experts?
 
P51 Mustang
A-10 Thunderbolt
P-38 Lightning
SR-71Blackbird
F-22 Raptor
F4U Corsair
SU-37 Berkut
C-130 Spooky
AIR FORCE 1
225-Antonov
 
Well, that's the answer now we gotta guess what the question was . . .

Haha! 😄 You’ve gotta go back four and a half years ago to the very first post….
IMG_5816.jpeg
 
Stupid questions for airplane people. Counter-rotating prop questions (I was looking at Tu95).
In ideal configuration>
1) do the axial rotation of outer prop and inner prop rotate at the same revs?
2) if they do, what is the (ideal) phase relationship?
3) what is the reality on Tu95 according to the above.

Helios with coaxial rotors>
same question series. 1,2,3

My WAG> fwiw the Tu seems to my eye to "answer" 1 > yes 2> there's maybe 5 or 10 degrees of phase shift.

as to helios, I have no real idea...

What say the experts?
I’m not an expert , but my understanding of counter rotating props , like the avro Shackleton , Tu-95 etc is that they rotate at the same RPM
I’m not sure of phasing , but I do know the 95 noise / vibration on full power run ups would make ground handlers physically sick …
 
For my birthday this year, my wife bought me a ride on a vintage aircraft. I chose this plane and we decided to go on the flight together. This is happening in June. 20 minute flight but should be a blast.



View attachment 243112View attachment 243113
This Friday is flight day. Hope it isn’t cancelled due to smoke from our wild fires. Will post pics if I become airborne.
 
I’m not an expert , but my understanding of counter rotating props , like the avro Shackleton , Tu-95 etc is that they rotate at the same RPM
I’m not sure of phasing , but I do know the 95 noise / vibration on full power run ups would make ground handlers physically sick …
Thanks very kindly. The "mechanical" or "engineering" histories from the old SU - and the (econo-political history too)..these fascinate me. The "inner design philosophy" that can be seen in the objects. When the Soviets sold themselves I was able to get all sorts of stuff from the loot...a clock, for example, from a Soviet submarine (it weighed about 2 kg!)...anyway the props - understanding the fluid dynamics ... I used to install and/or overhaul steam turbines...and picture the CR propset as having a phase relationship very approximately analogous to the relationship one would have if the turbine case with its diaphragm stages was rotating as one of the props, while the rotor spun as the other prop. Of course that's a hoot to imagine! But at design speed and load in an old GE steamer there is a phase relationship - each "mu" gets bashed in a sort of zigzag to the condenser...but I don't think it's spoken of in those terms.

They say the Americans never mastered the CR props (B-36) and such. If true I bet it wasn't for lack of brains, but because of somebody's greed. I'm going to take a trip into the history...I bet there's good old wind-tunnel and design data in some corner. Wright Field / Wright Patterson...they did all sorts of nifty stuff...I'll do some digging.

Maybe someday I'll get to hear avro Shackleton or Tu95. (the sexy patrol version of the Lancaster was new to me. Thanks!)

.................................................ok> I did some reading . It "turns (!)" out that there's a trade off between noise and less noise, and between speeds and blade number and the swept disk size...and most of the good stuff is behind paywalz...but I found two learned aeronautical papers and a good one on wet propellers. There's a lot of interest in the wet stuff, money on the table an' all. The papers I got will take some time to grasp, so far I only scanned and read a bit. Maybe >20% of the fuel can be saved, it seems, with some very sexy machinery.

Anybody wants to read the stuff, ask. I'll post title/urls

Best!
 
Last edited:
1686699429465.png

1686699565395.png


The McDonnell Aircraft Corp. XF-85 Goblin, the smallest jet-propelled fighter ever built, was a “parasite” designed to be carried by a B-36 bomber. If the host ship was attacked, the Goblin would be launched from the bomb bay to protect it. The Goblin was egg shaped and its wings — swept back 37 degrees — could fold upward. It had no landing gear and was launched from the bomber. It was then recovered using a hook and a retractable trapeze under the parent airplane. For emergencies, the Goblin had a steel skid under the fuselage and small runners on its wingtips.
It was named the Goblin because company founder James McDonnell had previously decided to name the company’s jet fighters after supernatural creatures. The Goblin followed the Phantom and the Banshee.
The tiny fighter was stable, easy to fly and recovered well from spins. However, hooking the Goblin in flight to its bomber’s trapeze was difficult. Its first fully released flight was on Aug. 23, 1948 at Muroc (now Edwards Air Force Base, Calif.). Lowered by the trapeze from the mother ship — a Boeing EB-29 nicknamed “Monstro” — McDonnell test pilot Ed Schoch released the Goblin and made three unsuccessful attempts to reconnect the X-85 to the trapeze, but the small jet was buffeted wildly by the larger jet’s turbulence. On the last attempt, the Goblin hit the trapeze with such force that the canopy was smashed. The pilot managed to make a belly landing using the Goblin’s skid on a dry lakebed.
Ultimately, only three of the seven flights of the Goblin resulted in successful connections with the arresting trapeze. The test program was canceled in 1949, and the Goblin never flew from a B-36. Docking had proved too difficult. But by that time, the Goblin was no longer needed. In 1949, the Boeing KB-29P, with its flying boom aerial refuelling system, had solved the problem of long-range fighter escort for bombers.
McDonnell built two prototype Goblins, and one joined the collection at the U.S. Air Force Museum at Wright-Patterson Air Force Base, Ohio.
.
More detail here: https://nationalinterest.org/blog/b...rasite-jet-built-defend-nuclear-bombers-61617

.
.
Information & image credits: boeing.com
 
Worlds first 4 engine jet biplane? :sneaky:
So, both the Germans and Americans experimented with what were, crude air launched cruise missiles in the second war

The lower aircraft is essentially an explosive filled weapon, that will use is engines to help get airborne, the whole thing is controlled by the pilot in the top aircraft

Once locked onto a target , the top aircraft detached, the lower one flys on to the target

Germany used this combination mostly with fw190 / ju88

American versions used a radio controlled B17, these were designed to go after German submarine pens. Idea here was a pilot got it off the ground , and a chace plane would then take over the guidance by radio , the b17 take off pilot would then bail out over England

One of these failed spectacularly and killed John Kennedy ( yes, that one!) who was flying chase .

The Germans did in fact have the first TV guided standoff air launched weapons , these were terrifying against ships to the point where their existence was not reported in the press for some time after the allies knew about them

I know TMI…I used to be a crew chief in a military museum lol
 
Saunders Roe flying jetboat. Pretty duck with guns. Pathe film clip.

http://www.astronautix.com/w/wasserfall.html I have read that Wasserfall, while never operational, did tests against B-17. 20 tests. 19 kills. True ? I was not there. Like glidebomb, not a good idea to chat it up while the blood is flowing yet.

I read many decades ago, that the US flew radiocontrolled P-38 over Japan. The controller being in a bomber, iirc. I probably read that in 1958 in a school library.

Best!
 
The tech gets “ interesting “, Luftwaffe also deployed the R4m air to air rocket , an effective and terrifying tool used against bombers
This is a B 24, allegedly hit by one of these
1687023560995.jpeg

The R4m was later developed into the 2.75 inch air to air missiles carried by the F-84, and up here in Canada, by the CF-100 all weather fighter
 
Back
Top