HERC JOV-3 & McCulloch MC-4

okikuma

Member
Joined
May 21, 2006
Messages
3,555
Location
Santa Clarita, CA
The JOV-3 certainly would be a fun helo to own. 4130 tubing and fabric covering certianly was a light airframe.

HERC JOV-3 & McCulloch MC-4
HERC JOV-3 & McCulloch MC-4
HERC JOV-3 & McCulloch MC-4
HERC JOV-3 & McCulloch MC-4
Development began in 1946 with the Helicopter Engineering and Research Corporation (HERC) in Philadelphia, headed by D.K. Jovanovich and F. Kozloski, where a small 2-seat prototype (N9000H) was built with the designation JOV-3. This aircraft, powered by a 125hp Lycoming O-290, was flown successfully in 1948.


Then there's the McCulloch MC-4 / YH-30. Heaver and a little bit more expensive to operate than the JOV-3

Wayne

HERC JOV-3 & McCulloch MC-4HERC JOV-3 & McCulloch MC-4HERC JOV-3 & McCulloch MC-4HERC JOV-3 & McCulloch MC-4
HERC JOV-3 & McCulloch MC-4
 
This is one of my favorite small helicopters. Its story didn't end on MC-4C - it was resurrected a bit later in the form of Jovair helicopters (which two pictures you mistakably posted) - Jovair 4E Sedan is the only one four-seater from this family.

Regarding original design, the HERC JOV3 - Mr Jovanovich tried to sell his project to the Hoppi-Copters Inc back in the late 40's. Thankfully at the end he sold it to McCulloch, so we are able to witness another chapter of its story - otherwise it would probably end with the Hoppi-Copter.

If you are interested in the MC-4 (4C) part, there is a great online book posted by the son of its test pilot, Mr C.W. Bayer (son). Be patient - it loads quite a time, but it presents lots of PDFs with brochures, articles, letters, drawings and so on, not only on MC-4 but also on Kellett helicopters and early Hughes':
 
Last edited:
On tandem rotors, how do you control them?
One collective with another axis for ratio?
2 sticks with axis and collective?

I have never seen the controls for a tandem.....
 
Controls (single set only) look identical to the standard familiar ones, but with some differential action on the rotors to achieve the same desired effects.
 
What is the differential action?
For/Aft axis on the collective?
 
For example, the pedals can be configured to produce differential cyclic to get yaw (remember there's no tail rotor). A pitch change can come from a relative change in collective.

You can rig up conventional looking controls that get conventional responses but do it through different techniques.
 
Last edited:
So I am wondering specifically about for/aft pitch, or collective ratio.
The pedals make complete sense.

Just watched this RAF Chinook, he's "Flying it Like a Gyro"!!😈

 
A friend of mine had to haul the power drive shaft that goes all the way from front to back in a Chinook.
He said it looked heavy, but when he went to pick it up, he almost tossed it, very light for it's size.
 
That's a great link, Wayne.
The best resource I know to answer Mark's question.

To help comprehend the combined differential action of each rotor system, take a look at the following photos and video. Note the angle of each rotor disk within the individual roll axis as compared to the other. It is subtle but noticeable if one watches closely.

Wayne

HERC JOV-3 & McCulloch MC-4HERC JOV-3 & McCulloch MC-4HERC JOV-3 & McCulloch MC-4

 
This is one of my favorite small helicopters. Its story didn't end on MC-4C - it was resurrected a bit later in the form of Jovair helicopters (which two pictures you mistakably posted) - Jovair 4E Sedan is the only one four-seater from this family.

Regarding original design, the HERC JOV3 - Mr Jovanovich tried to sell his project to the Hoppi-Copters Inc back in the late 40's. Thankfully at the end he sold it to McCulloch, so we are able to witness another chapter of its story - otherwise it would probably end with the Hoppi-Copter.

If you are interested in the MC-4 (4C) part, there is a great online book posted by the son of its test pilot, Mr C.W. Bayer (son). Be patient - it loads quite a time, but it presents lots of PDFs with brochures, articles, letters, drawings and so on, not only on MC-4 but also on Kellett helicopters and early Hughes':
Dziekuje Marcin for the updated information and the online book.

Wayne
 
The best resource I know to answer Mark's question.

To help comprehend the combined differential action of each rotor system, take a look at the following photos and video. Note the angle of each rotor disk within the individual roll axis as compared to the other. It is subtle but noticeable if one watches closely.

Wayne



They are definitely tilted to throw the rear end around in the turn like rear wheel steering, which in the rear view of the rear rotor in the right turn looks pronounced since it is tilting towards the retreating blade side.
I still want to know if you can control the for/aft power distribution, or lift at will...
 
While hovering, you can pivot about the front rotor mast, you can pivot about the aft rotor mast, or you can pivot about the midpoint between the two, depending on the ratio of pedal:lateral-cyclic control input you make. Fore/aft cyclic just varies the amount of collective pitch on the front rotor vs. the rear rotor. The collective pitch lever is called the thrust lever. Here's the actual stage 2 mixer.
HERC JOV-3 & McCulloch MC-4
 

Attachments

  • HERC JOV-3 & McCulloch MC-4
    1717667467143.png
    1.7 MB · Views: 50
Seven-segment "Sync-Shaft" that makes certain the two rotors never hit each other and are always 60 degrees phased.HERC JOV-3 & McCulloch MC-4
 
Last edited:
Forty Eight "MS-grade" bolts to fail along the Sync-Shaft. I think they're 1/2-20. Lots of vibration neutralizing labor
at factory assembly. Lots of vulnerable "flight critical" places for enemy projectiles to strike a fatal blow. HERC JOV-3 & McCulloch MC-4
 
1717672132560.png

My stick-buddy (Tim McCall) from flight school in 1987 (also picked CH-47's) and unlike me, stayed healthy and did 20 years. After retiring, he went to work for Boeing/Vertol and was responsible for delivering hundreds of CH-47F models all over the world. His teams trained all the pilots and got them "mission-capable" in the F. He gave many unit standardization check-pilots their checkrides also. Here's a picture they made as they passed Mt. Rushmore, on their way to Ft. Wainwright in Alaska.
 
Top