Just out of curiosity - Airplane Guys

[GLJ]

@Jim
Years ago (late 70s) when I was racing off road a club member also had a private plane. He did all his own work on his bikes and his plane. He had just rebuilt the engine in his plane. I was asking him about it because I thought it would be harder to do than a bike. He said the engine was easier. A lot lower rpms, more tolerance on clearances because it ran a lot less RPMs. I was surprised, like Mailman I thought they spun as fast as our racing bikes. He explained that the tip of the prop has to stay below the speed of sound. So that limited the RPMs to between 2500 and 3000 depending on prop length. Is that true?
I should ad he is a pretty sharp guy. Built prototype parts and the machines to make them. He raced Huskys.

 

[Jim]

more tolerance on clearances because it ran a lot less RPMs

Tolerances are actually about the same as any air cooled engine, regardless of rpm.

He explained that the tip of the prop has to stay below the speed of sound. So that limited the RPMs to between 2500 and 3000 depending on prop length. Is that true?

That's correct. Larger aircraft that used large (10-12ft dia.) props used geared engines so the prop would be at about 1500rpm with an engine speed of about 2500-3000 rpm. As you said, the limiting factor is keeping the tips subsonic.

 

[Jim]

He said the engine was easier.

That's also correct. It's a very basic vertical split case, pushrod engine. About as complex as a Briggs and Stratton mower engine.

 

[Grimly]

Alors, merde!
https://www.caranddriver.com/news/a32131240/french-dassault-fighter-jet-joyride/

 

[Boog]

How low is too low? Well this is still OK I suppose....

 

[Adamc]

There are safer ways to get a hair cut!

 

[Boog]

Just so no one gets the idea our brothers of old did not know how to live...

 

[fredintoon]

That's also correct. It's a very basic vertical split case, pushrod engine. About as complex as a Briggs and Stratton mower engine.

Hi Jim,
they are more complex than a lawnmower engine, for starters, even the simplest aero-engine has dual ignition systems, eh?
One of apprentice Freddie's first engine test bed jobs was to do the "mag drop" checks on Bristol Hercules & Centaurus radial engines. 800 rpm drops to 500 rpm left, 800 drops to 500 right & then on to the fuel consumption tests.

 

[MaxPete]

This came up on my YouTube feed this morning - quite remarkable.

As far as I know, this is an original ME163 from about 1944 but the rocket engine has been disabled. The fuel and oxidant that the Luftwaffe used were extremely toxic chemicals and thus very dangerous to handle and ride around with. Nonetheless, the airplane is a superb glider with delightful handling characteristics. The big downside is a lack of a real undercarriage with any shock absorbing ability (it landed on a skid with very stiff hydraulics).

Apparently, many 163 pilots were lifted out of the wreck with broken backs after flaring too high and stalling.

Operationally, the airplane could takeoff by itself and climb to more than 30,000 feet in about 3 minutes and then glide through the 8th Air Force bomber box formations at more than 500 mph - shooting all the way.

Overall, the 163 was far more dangerous to its own pilots and refuelling crews than it was to Allied aviators - but it did shoot down a few B17s and B24s with its twin 30mm cannon.

 

[gggGary]

Battery powered airplanes.
https://www.morningbrew.com/emergin...utm_medium=newsletter&utm_source=morning_brew

 

[halfmile]

Today on the VFT site.

 

[MaxPete]

Today on the VFT site.
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One of my closest friends was a chap named Sam Smyth. Sam was born in 1924 in Burbank CA and was the consummate airplane nut (exceeded possibly only by me….). He was a wee bit young for the beginning of WW2 but could have gotten in at the end except that he had bad lungs.

Instead, Sam used his considerable talent as a draughtsman at Lockheed’s big plant in Burbank. He attended Pasadena City College at night and worked there throughout the War. At the end, the Company sent him away to school at the Univ. of Colorado where he earned a degree in Mechanical Engineering and returned to Lockheed in about 1947 as a design engineer. He worked on the Constellation, Electra transports and F80 and F94 Starfire fighters and the P2V Neptune Patrol bomber ….and some other stuff that he wasn’t able to fully describe. In, I think, about 1950, he was recruited by Kelly Johnson and Ben Rich into the Skunk Works ADP group and from then on, his career became even more obscure. He did tell me that he was one of the first half dozen people to use a newfangled thing called Computer Aided Drafting (CAD) which Lockheed developed in the 1960s. The package was called CADAM and was eventually sold to Dassault who renamed it CATIA - and it is still widely used in the aerospace and auto industries today.

I met Sam in 1995 at the big SAE Aerospace Congress in Long Beach CA when he ran a history session at the Congress. I am proud to relate that I could answer every single question he posed to the crowd and the prize was lunch - with him. One of the questions was: what was the official designation of the V1 Buzz Bomb? Of course, the V1 was designed by Fiesler (of Fiesler Storch fame) and it was designated the Fi103. Needless to say, Sam and I became fast friends and visited back and forth until he died in 2012. I miss him to this day.

ANYHOW, Sam told a great story about Lloyd Stearman. At some point during the 1940s, Lockheed appealed for more engineers and Stearman came and applied for a job - along many other superannuated engineers - to help out the war effort. On the application form, there were two questions that got a strong response from the HR person who was interviewing the applicants:

1) Have you ever worked for Lockheed Corp. before?

Stearman answered that yes, he had indeed worked for the company previously.

2) If so - what position did you hold?

Stearman simply answered: President & CEO.

Apparently, that caused quite a rumpus in the Human Resources Dépt.

 

[gggGary]

Think you got some?
Drive this.

 

[Jim]

I've got an old book... prolly 40-50yrs old called The Worlds Worst Aircraft. The GB Racer is in it. Jimmy Doolittle flew it in several races and said it kept trying to kill him.
Beautiful, but a handful.... one of the worlds worst.

 

[gggGary]

Some Gee Bee background
https://www.militaryfactory.com/aircraft/detail.php?aircraft_id=384
Don't watch this.

 

[Jim]

I'll paraphrase Mr Gilbert from the book I referenced above...
All of the GB racers built crashed and were destroyed except for one. It sits in a field at an airport down in Mexico. I don't know what condition it's in. Bad I hope... lest someone be tempted to repair and fly it. Enough is enough.
Ahh... Mr Gilbert's dry humor.

 

[Jim]

Another pilot from Mr Gilberts book exclaimed, as he was being carted off on a stretcher (after crashing the Gee Bee)...
"The damned thing kept trying to bite itself in the ass,"

 

[MaxPete]

Yes indeed, the Granville Brothers (hence the name GeeBee) certainly knew how to create "exciting" airplanes....

 

[Downeaster]

Wowsers. He didn't even have time to say "Oh, shit!"

 

[Grimly]

Looks like a wing folded.