Twin F-100 Super Sabre Projects - Two Approaches to One Great Plane!

[DamoRC]

When Grifflyer posted his poll on what he should design next, I was touched by @jaredstrees comment that he would love to see the F-100 Super Saber because his father in-law flew one. Not being a native with no link to the military and seeing that the F-100 was not getting a lot of votes at the time, I went ahead and roughed up a design as a way to honor the pilot. Meanwhile the F-100 gained popularity as Grifflyer's next option. So we agreed we would do a joint design and build thread for the planes, each taking our own approach to the subject matter and each sharing the journey. These first posts will be updated at the end to summarize where we got to with our different approaches. As I understand it Grifflyer will be building a 50mm EDF version and mine will be a 70mm.

Anything to add @Grifflyer?

 

[Grifflyer]

You summed it up nicely, good luck with your build!!

(reserved)

 

[jaredstrees]

Sweet. You guys both rock. Looks like I'll have a lot of foam to cut soon. And Damo, I did manage to get a few pics and other info from my visit to My father in law's. We're still going through a lot, though. 40 years of accumulation in that house! I'll send it your way this week.

 

[jfaleo1]

I think this great guys. Consider flaps guys the real thing was a bear to land without them. I anxiously await both designs.

 

[Sheriff]

I have just maiden a F-100 using a 64mm EDF and a 3s 2200mha battery (flew ok, but need the 4s punch to fly well).
If you guys want to try this build, I got plans, but it's a BETA version: I was ajusting as I was building.

https://3dwarehouse.sketchup.com/model/dba511d7-99d5-40ba-b92d-eeb3f3a3d7b5/F-100-Super-Sabre

Au revoir

 

[DamoRC]

I have just maiden a F-100 using a 64mm EDF and a 3s 2200mha battery (flew ok, but need the 4s punch to fly well).
If you guys want to try this build, I got plans, but it's a BETA version: I was ajusting as I was building.

https://3dwarehouse.sketchup.com/model/dba511d7-99d5-40ba-b92d-eeb3f3a3d7b5/F-100-Super-Sabre

Au revoir

Looks like a really nice model and very similar to the approach I am taking on my version. Any pics of the build, flight vids?

 

[AkimboGlueGuns]

I don't know the exact figure, but to get the most out of an EDF you HAVE to make a constricting thrust tube. @Mid7night has better information than I do, but I think the figure is in the ball part of 85% of the fan swept area (area of the fan, minus the area of the motor.) To increase performance the tube should also be a smooth as possible. Not sure what you have planned, but if your past jet projects are anything to go off of this thing will be fantastic.

 

[Grifflyer]

@AkimboGlueGuns You pretty much got it all.

 

[Sheriff]

Great model DamoRC ! But will you be able to transpose all thoses polygones to reality?

I spent a lot of energy simplifing my model for ease of build while keeping the iconing shape.
Also to simplify, my wing has no ailerons (using elevons). The wing also as a bend to generate more lift and create a positive angle of attack in relation to the axis of the fuselage.

Here are pictures of the prototype. I will be back with better images and a video of the first (successfull) flight.

Au Revoir
Gui

 

[Sheriff]

…in the ballpark of 85% of the fan swept area…

If my memory serves me right, David Windestal said in the Saab Viggen build video; 120% of the total EDF area for intake and 80% of the area for the exhaust.

Au Revoir
Gui

 

[DamoRC]

First off - that plane looks amazing - really, really, great work. Maybe we should change the title of this thread to cover all three builds?

Great model DamoRC ! But will you be able to transpose all thoses polygones to reality?

Yep - this is the building style (rut?) that I have been using for a while now. See the Gee Bee R3 build for an example of this approach in action.

Great model DamoRC
I spent a lot of energy simplifing my model for ease of build while keeping the iconing shape.
Gui

This is where my design approach has some limitations - I don't have an artistic bone in my body - so I have to rely on trying to replicate a shape based on the drawings and cannot tease out those lines that provide the shape I want. You seem to have done an excellent job.

Great model DamoRC Also to simplify, my wing has no ailerons (using elevons). The wing also as a bend to generate more lift and create a positive angle of attack in relation to the axis of the fuselage.
Gui

I'll be using an airfoil as well, just isn't represented in the image. I'll simply be replicating the foil from the Diamond Build. I intend to use ailerons and elevators, probably no rudder. Hard part for me will be getting the EDF thrust tube to sit above the horizontal stabilizer which will probably be a full piece going through the fuse.

If my memory serves me right, David Windestal said in the Saab Viggen build video; 120% of the total EDF area for intake and 80% of the area for the exhaust.

I think the inlet and outlet is greatly influenced by the geometry and the specific EDF unit you have but I don't disagree with the 120% inlet. 80% on the outlet is about as small as I would be willing to go. Based on my limited experience each EDF will have an optimum exhaust diameter for max static thrust, somewhere between 85% and 95% FSA.

 

[Sheriff]

Thanks for all your nice comments.

I see the airfoil now, it shows on the side of the fuselage. I suppose the fold will also help with strength.

Yes, your horizontal stabiliser will interfere with your thrust tube, if you keep the original Super-Sabre shape. I wanted to make an all-moving horizontal stabiliser but went with the simpler option because of the conflict in space.

Yes, I guess each EDF fans comes with specifications for the intake/exhaust area. I should look it up for my model. Thanks for the tip.
I cheated my intake by adding guilds on the fuselage underside (to preserve the look) but it sucks in debris on landings; not the perfect solution. I love the side-scopes on your Diamond; it might even help by accelarating the airflow on the top of your wing-root.

au revoir
Gui

 

[jfaleo1]

“Hard part for me will be getting the EDF thrust tube to sit above the horizontal stabilizer which will probably be a full piece going through the fuse.”

If it were me I would consider using to separate stabilizer halves and two servos to run them.

This eliminates the carry through and thrust tube interference. Also a full flying stab would be scale but not nessssary I am fairly sure at the speed we fly. Just remember to double the the thickness oh the stab(not elevator) and use a reinforced triangle “stock” to top and bottom. Airfoil the Stab to take off some weight.

As for the use of elevens (tailerons) I am against them as a rule. While easy, I feel that it changes the flight characteristics to much and they are far from scale until you get to some modern fighters ( f14 notably). But we all have opinions. For whatever it is worth which is not much.😀

 

[Sheriff]

"As for the use of tailerons, I am against them as a rule. While easy... "

I would like to see how people usually build tailerons. I never found a simple/cheap/solid way to attach the surface through a single pivot point.

I appreciate your rule to keep model as close to the original as possible (and did not know the tailerons and all-flying tailplane were not invented together). But I prefer to skip the aileron to simplify the design and save weight. Also I feel that ailerons often get you in trouble at lower speeds by adding drag and stalling the wing you are so desperatly trying to prop up to save yourself from crashing.

Au revoir
Gui

 

[Grifflyer]

...I'll be using an airfoil as well, just isn't represented in the image. I'll simply be replicating the foil from the Diamond Build. I intend to use ailerons and elevators, probably no rudder. Hard part for me will be getting the EDF thrust tube to sit above the horizontal stabilizer which will probably be a full piece going through the fuse...

Why not try an all moving stab? I doing one with a BBQ skewer going through the fuse to hold both stabilizers, and mounted a single servo externally to free up interior space for the thrust tube, and it looks like I'll have decent room for a thrust tube. Maybe you could try something similar.

How are you going to go about storing your electronics? It looks like I'm going to have enough room for my ESC and receiver, but battery placement is going to be tough.

 

[Sheriff]

"Why not try an all moving stab? I doing one with a BBQ skewer going through the fuse to hold both stabilizers…"

Any picture of how you did it? Is it only at the concept level for now?

merci
Gui

 

[DamoRC]

Why not try an all moving stab? I doing one with a BBQ skewer going through the fuse to hold both stabilizers, and mounted a single servo externally to free up interior space for the thrust tube, and it looks like I'll have decent room for a thrust tube. Maybe you could try something similar.

How are you going to go about storing your electronics? It looks like I'm going to have enough room for my ESC and receiver, but battery placement is going to be tough.

I will think about the all moving stab as an option. Thanks for the suggestion

On the electronics, because I am building a 70mm version, I am keeping it a little on the large side (40 inch span in the current model) so I have loads of empty space in the front for batteries and stuff.

 

[Grifflyer]

I will think about the all moving stab as an option. Thanks for the suggestion

On the electronics, because I am building a 70mm version, I am keeping it a little on the large side (40 inch span in the current model) so I have loads of empty space in the front for batteries and stuff.

Okay I'm going for around 28 inch.

 

[DamoRC]

Okay I'm going for around 28 inch.

Makes sense for the 50mm.

 

[Chuppster]

Why not try an all moving stab? I doing one with a BBQ skewer going through the fuse to hold both stabilizers, and mounted a single servo externally to free up interior space for the thrust tube, and it looks like I'll have decent room for a thrust tube. Maybe you could try something similar.

How are you going to go about storing your electronics? It looks like I'm going to have enough room for my ESC and receiver, but battery placement is going to be tough.

I highly recommend you use music wire to join the stabilisers. That way you can bend them at 90 degree angles at the ends and form a "torque rod" so they don't start slipping.

I don't know the math on this, but the positioning of the pivot point on the stab matters. The further forward you put it, the more stable your tail will be, but the servos will have to work harder. The further back you put it the more unstable it is.

I hope you get the full flying hstab to work. I think they are awesome.