UH-1B vs. UH-1c Dimensions Challenge

The UH-1B has a horizontal stab width of 22.5 inches.  Each stab is 46 in. long and ~3.3 inches thick at the maximum thickness.  I know these measurements because i made them myself.  The UH-1C had a horizontal stab width of 28 inches and a total span of 9ft 4inches across both elevators.  That is from Wayne Mutza's Huey Gunships walkaround.  Tail fin dimensionas are harder to do because the width changes throughout it's length.  However, I can tell you that the UH-1C had the tailfin cambered 6 degrees.  Sorry I can't be of more help with the tailfin.  Exactly where are you trying to get measurements from?  As for fusealge length, Mutza reports the Uh-1B at 38 ft 5 in. While Chant (Be4ll UH-1 Super Profile) and Scutts (UH-1 Iraquois/AH-1 Hueycobra) reports the UH-1B 39ft 7.5 in.  As for the length of the fuselage in the UH-1C, all I have is the Chant measurement which he states is 42ft 7in.  I'm a  dubious about the Chant numbers since he also reports the UH-1H as having a 42ft fuselage.   By the way, Scutts reports the UH-1H as having a 41ft 10.75 in fuselage. Some of these measuremets are clearly wrong!  This question definitely points to the need for hands on measurement as far as I am concerned.  I'll look around for more resources, but that's what i got at the moment.  Maybe a Bell represenatative can clear this one up.

   Ray
 

Edit:  Here is the list of dimensions from the UH-1B dash 10:

[img]http://

Here is a diagram from the Uh-1C dash 10 (there was no diagram I could find for the UH-1B):

[img]http://

You will notice that the "length" you report depends on where it's taken from and to.  Also, you will note the measurement I would call "fuselage length" (i.e. nose of cabin to tail rotor guard is  39ft 6.35in in the Bravo and  39 ft 6.35 in. in the Charlie.  I would say that the fuselage lengths were basically the same based on these officially reported measurements.

Thanks, Ray. The stab width is a start, and will help me. I think for the tail fin, measuring along the top of the boom, from the panel gap just in front of the 42 degree gearbox vents, horizontally to the rear of the fin would be close enough. I've tried scaling up measurements from 1/48, 1/35, and 1/24 models and comparing them, and I got that the 'C' had about 6in. more chord, but needed confirmation. I think the chord of the tail fin is also 6in. more on the 'C' but, that still needs verification.

Agree on the inacurracies of stated measurements. They go all over the place. Some of the confusion may result from the various measurements as you showed in the dash-10. There are 4 different ways to measure the length. The authors you mentioned quoted one or the other, depending on their preferences.  A.J. Pelletier, in "Bell Aircraft since 1935" even quotes different lengths and HEIGHTS between the 'B' and 'C'.

What I would like to know is, is the 'C' chord 6 inches greater than the 'B' chord, and how was that increase achieved... move the leading edge of the fin forward?, move the trailing edge back?.. or a little of  both?

If yur not in a hurry, I'll get those masurements the next time I go to Rucker.  As for the measurement discepencies, yeah, I think your on the money and it depends on which measurements they used frm teh dash 10.  By the way, If you look at the line drawing from the C model dash 10, the tail fin looks exactly like the Bravo.  I've noticed that a lot in manuals that they just use figures from older versions.  Therefore, I'm not convinced of their accuracy either.  Rucker has a couple of Charlies in storage.  If I get to go back soon, I'll do my best to measure them.

Here is a comparison between the Charlie tail (top) and Bravo tail (bottom) and I think it is clear that the increase in chord came from moving the trailing edge back.   What do you think?

    Ray

Is it just me or does the chord at the root of the tailfin on both birds look the same?
 

[img]http://" border="0" />[/img]

OK, you got me curious so I went through all the pics i had looking for a straigt on side shot of both a Bravo and a Charlie.  Here's what I got:

An early Bravo (high vis paint, bell mouth intake):

" border="0" />

An early Charlie test bird from 1967 (note that the first ones off the line had teh bell mouth intake):

" border="0" />

I superimposed these in Photoshop and came up with this;

" border="0" />

As you can see the fuselages match up perfectly unitil you get to the tail fin.  I would say that based on this comparison, the Charlie model is at least a foot longer than the Bravo.  I know there is paralax and other optical phenomena that may account for some of the difference, but the rest of the birds match up great except for the tail, so I think this difference is real.  Also notice the height ofthe two, including the rotor mast is essentially the same.  I will admit that since these are early examples there may be differences that were incorporated into later lots of aircraft, but if there were, i'm not aware of them.  Does this help?

  Ray

No hurry on the measurements, Ray. Got to agree with you about the increase in chord came from moving the trailing edge back. I'm looking especially at the tip of the tailboom, ( that last little part, marked 'no push' on the 'B') the curve on the underside of that part is shallower on the 'C' than it is on the 'B'. My best guess is maybe a six inch increase in chord, but the increase didn't affect the tailrotor guard location or length ( but the sheetmetal around it covered more of it, because it appears shorter in the picture)  so that dimension didn't change. Because the chord increase was to the trailing edge, the dimension measured from the from of the fuselage to the tailrotor hub didn't change either. Hey, problem solved!

By the way, is that the Sioux Scout behind the 'C'? Someday, when my modeling skills get better, I might try scratchbuilding one of them.

Thanks for the help, and the pictures.

Joe

Ray, I must have been typing while you were posting. Just saw the photoshop images. That's really neat, and it does look to be maybe a foot difference between the two models. Does it help? Darn right it does. 

 Many thanks, that's great work.

 Joe

Joe,

  Your welcome and great eyes, by the way.  Yes, that is the Sioux Scout.  In fact, here are some shots of her to get your scatchbuilding juices flowing:

[img]http://[img]http://[img]http://[img]http://[img]http://[img]http://[img]http://[img]http://[img]http://[img]http://[img]http://[/

GOD BLESS MOTHER RUCKER!

    Ray
 

   Joe,

I just dug out my Bell Helicopter Products Reference Guide (circa 1968) and dug through the measurements. based upon bell's demensions, the comparisons follow.

Main rotor diameter/chord...... B 44ft/21in  C 44ft/27in

Nose to center of mast......... Both 11ft 7 1/2in  

Length (measured from nose to center of tail rotor drive shaft).....Both 38ft 4 & 27/32in

Length (measured from nose to outside of tail rotor diameter) ......Both 42ft 7 &27/32in 

Here's where the optical illusion takes place; I believe the C model fin is actually shorter than the B model fin. Measured from the ground to the center of the tail rotor drive shaft, the height of the B model fin is 10ft 6 & 1/4in; the C model fin is 9ft 6 & 27/32 in in height. Additionally, the B model tail nav light is 6ft 3 & 1/2 in above the ground reference line while the C model light is only 5ft 3 & 27/32 in above the line. The fin is cambered 7 degrees from the centerline to unload the tail rotor during high speed manoeuvers. The effect of increasing the chord of the fin shifted the center of gravity and required the 90 degree gearbox to be moved back on the fin. I can find no data on the width of the chord increase.

Synchronized elevator is 9 ft 4in in span on both the B and C. The chord is 22in on the B and 30 & 1/2 in on the C. In addition the b model elevator was symetrical in airfoil while the C was asymetrical (reverse airfoil, with flat side up). The fin was cambered 7 degrees from the centerline to unload the tail rotor during high speed manoeuvres.

Snakedriver,

  Looks like Bell's measurements don't match the ones Mutza reports for the Charlie Horizontal stab width.  Also, since the height of the tail measurements are given from the ground, if the Charlie sits back on it's skids farther, the measurements would be less.  If you check the superimposed images I posted above, I don't see how the tail could actually be shorter in the Charlie model.  What do you think?

     Ray

Ray,

  I am still grinding through the references I have and keep coming up with new information. Some C model data can vary depending upon which C model we look at. The first "C" model platforms were B models with a 540 rotor system and uprated engine. I've found two references for empty weights that vary as much a 200lbs. for the C model. I flew both, but I'll be darned if I can remember the differences other than the obvious. The C model sat a little more squat than the B model when it was loaded, but empty, which is what I believe the Bell specs are based upon, they were seperated by about 300 lbs in weight. The C model grossed out at about 1000 lbs over the B model, which put a little spread in the skids. Empty, the skid "spread was 8ft 4 & 7/16" for both models according to the Bell specs.

To add more mud to the water, I read a reference on-line that stated the C model tail rotor blades were wider in chord than the B model. i don't have any specific data to refute or support that information.

The -10 line drawing and demensions you put up for the C Model appear to be the same as published in the Bell Product Reference Guide. I would therefore be inclined to believe the B model demensions from Bell. Does Mutza reference his data source in the walk around?

Snakedriver,

  Check you e-mail.

          Ray

Wow. I thought it would just be'... the tail fin was increased in chord by six (or whatever) inches, and 7 degrees of camber were incorporated..'.

Had no idea it would be this confusing or contradictory.

You gentlemen are being a great help, though, and I do appreciate it.

Joe

Grandad,

  I hear ya there!  However, We DO know the main rotor dimensions for both the B and C with certainty.  Italeri, are you listening!  Even the blades on their 1/72 Bravos scale out four feet short!  And no trim tabs.  Since they use the same rotors on their B, C, and F models, they are all basically useless without help.  Maybe I'm being picky, but the rotors are one of the main things that makes a helo model to me.  Anyway, We'll get this measurement discrepency straightened out one way or another.  That's why I have to get back to Rucker with a tape measure and work with the Charlie this time!

     Ray

 Don't know if you saw this: a UH-1B on ebay. Sold on Christmas Day, for $45,100 (low monthly payments available). Wish I'd known. Could have bought it (yea, sure), measured it, and either kept it for my first 1/1 scale model, or donated it to a museum.  

cgi.ebay.com/ebaymotors/Bell-204-UH-1B-HUEY-the-original-gunship-of-Vietnam_W0QQcmdZViewItemQQcategoryZ63677QQihZ016QQitemZ260195488133QQrdZ1QQsspagenameZWDVW

Man, i wish I could aford to buy one even in that condition.  did you notice she was definitely a gunship because the bracing and nose plate is there to mount a 40mm M5 Thumper.  definitely a cool ship to own!

    Ray