Quantcast

High wing older designs

The Rocketry Forum

Help Support The Rocketry Forum:

Aeronerd

LPR, Gliderholic
Joined
May 30, 2020
Messages
65
Reaction score
21
Been looking at all the magazines on the nar website and noticed something about the older glider designs. They are what I think are called “high wing”. Anyone know why? Here’s one from 1980. See how the wings sit on a higher part of the fuselage? Nowadays the wings sit on a flat top fuselage.
High wing.jpg
 

TheAviator

Well-Known Member
Joined
Jan 18, 2009
Messages
829
Reaction score
16
I think it's mostly to get more material up in the fuselage. Looking at it from another perspective, the aft part of the fuselage is relieved to reduce the weight of the fuse and lessen the need for nose weight.
 

mooffle

Well-Known Member
TRF Supporter
Joined
Apr 20, 2020
Messages
110
Reaction score
62
That could be part of it. It also may be less about the wing, as that looks even with the engine, and more about getting the tail further from the exhaust.
 

o1d_dude

'I battle gravity'
TRF Supporter
Joined
Jan 18, 2009
Messages
8,179
Reaction score
1,031
Location
Planet Urff
Nowadays many gliders use a CF tube for a fuselage and adding a “shark head” to raise the wing is extra work for something that will probably fly away in a booming thermal.

I did it anyway to get the rear stabilizer out of the wing turbulence and to provide a place to mount a silly putty dethermalizer timer to “pop” the wing up. In the old days, we used D/T fuse and rubber band system.

Most gliders now also use an underslung vertical fin and dihedral in the rear stab.
 

Ez2cDave

Well-Known Member
TRF Supporter
Joined
Jan 18, 2009
Messages
3,789
Reaction score
1,015
My instinct is telling me that the designer thought it beneficial to get the Stabilizer out of the "Aerodynamic Wash" generated by the Wing, during flight.

Thoughts :

(1) More stable, since the "wash" would change with airspeed . . . Perhaps making it less prone to flutter during Boost ?

(2) Some trimming advantage ?

Dave F.
 

Alan15578

Well-Known Member
Joined
Feb 11, 2018
Messages
364
Reaction score
92
The wing downwash may be a bit lower than you think. If you want to move the stab farther from the downwash effects, move it up with a T-tail. Lowering the stab simply keeps it farther from the motor exhaust.
 

Ez2cDave

Well-Known Member
TRF Supporter
Joined
Jan 18, 2009
Messages
3,789
Reaction score
1,015
The wing downwash may be a bit lower than you think. If you want to move the stab farther from the downwash effects, move it up with a T-tail. Lowering the stab simply keeps it farther from the motor exhaust.
I was thinking only of the aerodynamic forces during boost, not during low-speed ( gliding ) flight.

As for the T-Tail, I suspect that it would be a weaker design, structurally, since the entire Empennage would only be bonded to the Fuselage at the base of the Rudder. Also, I think there would be a lot of "Torque" ( twist / flutter ) acting on the Rudder itself. It would be subject to the "double-whammy" of airflow and exhaust turbulence.

I can't recall ever seeing a T-Tail BG or RG, design . . . ?

Has anyone ever done any Wind Tunnel analysis on Gliders, especially at high velocities, simulating Boost conditions ?

Dave F.
 

Aeronerd

LPR, Gliderholic
Joined
May 30, 2020
Messages
65
Reaction score
21
Nowadays many gliders use a CF tube for a fuselage and adding a “shark head” to raise the wing is extra work for something that will probably fly away in a booming thermal.

I did it anyway to get the rear stabilizer out of the wing turbulence and to provide a place to mount a silly putty dethermalizer timer to “pop” the wing up. In the old days, we used D/T fuse and rubber band system.

Most gliders now also use an underslung vertical fin and dihedral in the rear stab.
Getting stab out of wing downwash makes alot of sense. I thought it maybe had something to do with high wing planes being mor stable because of what was called pendulum effect.
 

Aeronerd

LPR, Gliderholic
Joined
May 30, 2020
Messages
65
Reaction score
21
I was thinking only of the aerodynamic forces during boost, not during low-speed ( gliding ) flight.

As for the T-Tail, I suspect that it would be a weaker design, structurally, since the entire Empennage would only be bonded to the Fuselage at the base of the Rudder. Also, I think there would be a lot of "Torque" ( twist / flutter ) acting on the Rudder itself. It would be subject to the "double-whammy" of airflow and exhaust turbulence.

I can't recall ever seeing a T-Tail BG or RG, design . . . ?

Has anyone ever done any Wind Tunnel analysis on Gliders, especially at high velocities, simulating Boost conditions ?

Dave F.
Correct about being weaker. Anyway I haave never seen a T tail either. And besides it would have to be on the BOTTOM of the boom so it wouldn't get burned.
 

Alan15578

Well-Known Member
Joined
Feb 11, 2018
Messages
364
Reaction score
92
Correct about being weaker. Anyway I haave never seen a T tail either. And besides it would have to be on the BOTTOM of the boom so it wouldn't get burned.
I was certainly not advocating for T tails on B/Gs, just making a counter point. However, I have seen T tails on real sailplanes.
 

Aeronerd

LPR, Gliderholic
Joined
May 30, 2020
Messages
65
Reaction score
21
No judgement it's all good. Just commenting I have yet to see a rocket glider with that kind of tail. Maybe I'll come across one in one of those old rockestry mags on the nar website
 
Last edited:

Rktman

Eric
Joined
Mar 5, 2017
Messages
1,037
Reaction score
77
Actually there is (or was) a glider that did employ a T-tail: the Centuri Mach 10. It's “glide” left something to be desired though, as it descended rapidly in something best described as a “controlled fall” due in part to that T-tail. The stab part was actually mounted facing forward, acting almost like a drag brake to compensate for the offset thrust line of its motor tube. It wasn't uncommon for its flight path to include a scalp-removing loop unless you used a higher thrust motor than an A or B. It was rather cool looking though, and a great attention getter.

scratch_upscale_mach10_04.jpg

Dynasoar Rocketry’s Mach 2 also had a T-tail, though the RC glider's flight path was primarily controlled by the wing ailerons.

9d30d57bbfe58952ede3695b82ce702e9839.jpg
 
Last edited:

Ez2cDave

Well-Known Member
TRF Supporter
Joined
Jan 18, 2009
Messages
3,789
Reaction score
1,015
Eric,

I remember almost "getting my hair parted" by a Centuri MACH-10, in the mid-1970's. Whoever built it never put the "clay ballast" in it. It looped VERY TIGHTLY, just off the Launch Rod . . . Got my attention !

Dave F.
 
Top