Cessna UC-78 Bobcat

 

Cessna UC-78 Bobcat - plan thumbnail image

Cessna UC-78 Bobcat - completed model photo more pics (2)

Cessna UC-78 Bobcat  
by B Morse, M Hickman
from RCMplans (ref:122)
1964 
66in span
Tags: Scale IC R/C Multi
all formers complete :)
got article :)


This plan was found online 13/12/2011 at: http://www.rcgroups.com/forums/showpost.php?p=20015183&postcount=7240
Outerzone planID: oz2016 | Filesize: 767KB | Format: • PDFbitmap | Credit*: 50+AirYears, JJ

   

About this Plan

Cessna UC-78 Bobcat. Scale twin for radio control.

Quote: "As you took your first glance at the Bobcat you probably wondered what kind of a nut would spend all that time working on such an ugly duckling. But if you stay with it long enough, you will feel as we do - it's so damned ugly that, in real truth, it has a beauty all its own.

The model is an excellent flier with only one major vice - it does like to drink fuel! If you start a UC78 of your own, get a gallon of fuel now!

There is no magic secret in the de-sign of the model. The Cessna engineers took care of these when they designed the full scale T-50 in 1939. The only deviation from scale is the fabric covered wing being replaced by conventional RC wing construction for greater durability, plus the substitution of a modified NACA 2417 airfoil. The ship is extremely stable and responsive, and to date, without vices. We are most emphatic in recommanding the use of contra-rotating propellers to cancel the torque effect. With two 35's screaming away, this torque could be a real problem - if not disastrous. Models to date have used K&B 35 R/C mills with the left hand engine equipped with a reverse ported crankshaft (usually available from the manufacturer).

Propellers used were Tornado 10-6, right hand and left hand. Prototypes #3 and #4 are now being built. #1 met its demise at the 1963 Indian City meet in Detroit when the elevator pushrod went out with the engine in high speed! #2 is in mint condition and was recently displayed at the 1964 Fresno, California Open contest. While we do not recommend the Bobcat for the beginner, the aver-age sport multi-flier can fly this ship without any difficulty if he has any degree of faith in his flying ability.

Very few problems are encountered in constructing the model. The fuselage is large, but light. The wing is no more difficult than the average contest multi wing with the exception of the two nacelles that are built-on after the basic structure is finished. DO NOT increase wood thickness anywhere in the model as this is the only area where you can keep the weight down. (Come to think of it, you'd better get some more fuel!).

The eight ounce DeBolt metal clank tanks should have 3/8'" trimmed from their length so that they will fit be-tween the firewall and sheeted wing leading edge. DO NOT cut into the leading edge to install standard tanks, as this will seriously weaken the beam strength of the leading edge box struc-ture. Assembly of the nacelles starts with the installation of the main vertical plywood keel..."

Update 20/12/2013: Replaced this plan with a full version showing all formers and ribs, thanks to JJ.

Update 08/08/2017: Replaced this plan with a modified version which shows fuselage datum line and CG location, thanks to zipman, davidterrell80, rchopper56.

Supplementary files

Article pages, text and pics, thanks to TravisM.
Previous scan version (includes 2 pages additional drawings).

Corrections?

Did we get something wrong with this plan? That happens sometimes. Help us make a correction

 

User comments

No comments yet for this plan. Got something to say about this one? Click here to Add a comment

 

Notes

* Credit field

The Credit field in the Outerzone database is designed to recognise and credit the hard work done in scanning and digitally cleaning these vintage and old timer model aircraft plans to get them into a usable format. Currently, it is also used to credit people simply for uploading the plan to a forum on the internet. Which is not quite the same thing. This will change soon. Probably.

Scaling

This model plan (like all plans on Outerzone) is supposedly scaled correctly and supposedly will print out nicely at the right size. But that doesn't always happen. If you are about to start building a model plane using this free plan, you are strongly advised to check the scaling very, very carefully before cutting any balsa wood.

 

Terms of Use

© Outerzone, 2011-2018.

All content is free to download for personal use.

For non-personal use and/or publication: plans, photos, excerpts, links etc may be used, provided that full and clear credit is given to Outerzone with appropriate and specific direction to the original content i.e. a direct hyperlink back to the Outerzone source page.

Unauthorized use and/or duplication of this material without express and written permission from this site's owner is strictly prohibited. If we discover that content is being stolen, we will consider filing a formal DMCA notice.