Lockheed YO-3A Quiet Star

[flateric]

http://pimaair.org/project.php?rid=21

 

[Mark Nankivil]

Greetings All -

A donation to our Museum earlier this year included a Pilot's Handbook for the YO-3A. Attached are a few drawings and diagrams from the manual.

Enjoy the Day! Mark

 

[AeroFranz]

very nice, Mark. Thanks!

 

[Stargazer]

Beautiful, Mark. Thanks, and have a great New Year!

 

[Maveric]

a nice pic of the YO-3A (Aviation Magazine)

 

[yahya]

I have a question related to the Lockheed YO-3 Quiet Star avionics suite from the Vietnam war. This site https://randallmalmstrom.wordpress.com/2020/06/01/lockheed-yo-3a-quiet-star/ contains some photos documenting the cockpit from the 1960/1970s, which contained legacy avionics suite compared to the one from the flight manual listed above.

I was able to recognize the following avionics pieces:

C-6533 ICS
AN/ARC-51 UHF COM
Collins 618F-1A VHF COM
AN/APX-72 IFF

What bothers me is the presence of the ID-250 RMI with two needles in the center of the instrument panel and the ID-249 Course indicator on the right side of the instrument panel. I do not have the proper YO-3A flight manual to consult with, and I am not sure if these indicators were used with the AN/ARN-21 TACAN or the AN/ARN-14 VOR navigation systems on this bird, or with the ADF. The control panel for the nav is unfortunately not visible, so it remains a puzzle whether TACAN, VOR or ADF were originally used in the early YO-3A. Can our experts please help verify what types of TACAN, VOR and ADF were used in the early setup?

Source: https://randallmalmstrom.wordpress.com/2020/06/01/lockheed-yo-3a-quiet-star/

 

[yahya]

I did some small research regarding the nav equipment of the YO-3A.

It seems to me that there were two TACAN setups. The early one consisted of the following items:

AN/ARN-21 TACAN (or later, particularly 28V DC-powered solid-state ones) + ID-250 RMI + ID-249 Course indicator.​

The newer one as described in the scans of pilot's manual as posted above consisted of the following pieces of rig:

AN/ARN-52(V) TACAN with the C-2010 control head + ID-387 TACAN indicator + ID-663 TACAN indicator.​

As far as the ADF is concerned, it seems that this setup was used on newer YO-3As:

AN/ARN-89 ADF with the C-7392 control head + the ID-1351 ADF indicator​

I do not know which ADF, if any, was used on the older version. However, if the ID-250 RMI was ideed used, I guess the compatible AN/ARN-59 or the AN/ARN-83 could have been installed.

Any suggestions and comments are welcome.

 

[riggerrob]

a nice pic of the YO-3A (Aviation Magazine)

With a cockpit only one seat wide, the fuselage is clearly based upon the earlier Schweitzer 2-32, 3-seater glider.

The late RG-8A surveillance airplane was based upon the wider TG-7A motor-glider used by the US Air Force Academy.

 

[jackssmirkingrevenge]

https://imgur.com/xkLHe1n

Footage of Lockheed Q-Star N57135 converted from a Schweizer SGS 2-32 glider as a proof of concept during the initial development of the YO-3

 

[hangar3]

Hello,
Does anyone have a link to the flight manual of the Quiet Star? Really curious to see illustrations of how the engine RPM was geared down, and whether there was a fixed prop or a constant speed prop!
Thanks!

 

[Sabrejet]

I wouldn't expect that to be in the Flight Manual; more likely to be in Maintenance - General Airplane or possibly the Powerplant TO.

 

[Stargazer]

There were different propellers used on the O-3, ranging from three to six blades (see photos below).
The item I'm sharing below indicates speeds "as low as 500 rpm", which, along with the images, suggests variable speed props.

 

[aim9xray]

RPM reduction accomplished via V-belts (like accessory drives in automobile engine; many, side by side) and two pulleys (engine crankshaft - small, and propeller - large). Should have a picture this weekend. (maybe)

Here's a photo from John Shupak/Skytamer.com:

 

[allysonca]

Had a chance to buy one from a friend back in the day for not much money. Was told it was a bit of a handful to land, especially given the winds at my home airport Chino so I stupidly passed.

 

[aim9xray]

Oh! FULL size?

 

[allysonca]

Oh! FULL size?

Yepp... a real one.

 

[aim9xray]

Desk models are so MUCH easier to control in a crosswind especially when you make "whoosh" noises!

 

[hangar3]

There were different propellers used on the O-3, ranging from three to six blades (see photos below).
The item I'm sharing below indicates speeds "as low as 500 rpm", which, along with the images, suggests variable speed props.

500rpm! Wow! Thank you for sharing those pictures!

 

[hangar3]

RPM reduction accomplished via V-belts (like accessory drives in automobile engine; many, side by side) and two pulleys (engine crankshaft - small, and propeller - large). Should have a picture this weekend. (maybe)

Here's a photo from John Shupak/Skytamer.com:
View attachment 746028

That is interesting, seems like a LOT of V-belts!

I guess they just must have had the oil supply for the constant speed propeller/governor coming through the center of the white shaft that's part of the reduction system/ v-belt pulleys system?

 

[BLACK_MAMBA]

... and whether there was a fixed prop or a constant speed prop!
Thanks!

The initial six-bladed prop was a fixed pitch propellor, while the later wodden three-bladed propellor was a constant speed one (variable pitch).

See more here: https://www.yo-3a.com/short-history

 

[aim9xray]

Per the above website, 12 v-belts for the Lycoming engine. 3.33 to 1 reduction.

Highly recommend the site!