Solved FT Spear - Winglets or Center Fin?

[dap35]

I got inspired by a video from the FTCA that showed an EDF version of the FT Spear. I happen to have a pair of EDFs laying around and a spare FT Spear speed build kit.

My question to the community is has anyone flown the spear without the winglets and just used the center fins? I have flown with just the winglets before, but thinking that side arm launching would be even easier without the winglets.

 

[Merv]

... has anyone flown the spear without the winglets and just used the center fins?...

I have flown the Versa with and without winglets, currently flying without. It flys fine either way.

Without there is a bit of waggle. The winglets broke off in travel, I have not taken the time to replace them yet.

 

[Tench745]

I have only flown the Blunt-nose Versa, but have flown with and without winglets. The wing sweep is what provides most of the yaw stability on these wings, but the winglets help dampen out the last bit of "waggle".

 

[L Edge]

You have an interesting and intriguing project there.

My suggestion is to add 2 vert stabs to it in near the center. Then see if you can get it to fly. From the picture, it looks like you have upthrust to the EDF's?
Hope you remember up reflex is used with wings, This will add to it. If you do get it going, then slowly trim the verts and see if it works with none.
Also, did you know if it does fly, set up differential thrust for yaw to compensate for the proper amount in a turn. Then in your tx radio, use the aileron to rudder mix to program the turn.

Please make a video of whatever happens.

The first project I chose to play with a wing with no vertical stabs was the X-47 B using 1 EDF and 2 servos and no vertical stabs. Used a thrust vectoring nozzle to incorporate the correct yaw in turns. Went threw a bunch of sudden stops till I got it right.

 

[dap35]

You have an interesting and intriguing project there.

My suggestion is to add 2 vert stabs to it in near the center. Then see if you can get it to fly. From the picture, it looks like you have upthrust to the EDF's?
Hope you remember up reflex is used with wings, This will add to it. If you do get it going, then slowly trim the verts and see if it works with none.
Also, did you know if it does fly, set up differential thrust for yaw to compensate for the proper amount in a turn. Then in your tx radio, use the aileron to rudder mix to program the turn.

Please make a video of whatever happens.

The first project I chose to play with a wing with no vertical stabs was the X-47 B using 1 EDF and 2 servos and no vertical stabs. Used a thrust vectoring nozzle to incorporate the correct yaw in turns. Went threw a bunch of sudden stops till I got it right.

LOL..... I usually refer to those as rapid deceleration events

The EDF's in the picture havn't been glued in yet, but will be parallel to the wing. I am planning on trying differential thrust - it is going to have an Aura 5 that I pulled from a retired airframe.

 

[SlingShot]

I have a stock Spear. I sidearm it without much difficulty.

 

[L Edge]

LOL..... I usually refer to those as rapid deceleration events

The EDF's in the picture havn't been glued in yet, but will be parallel to the wing. I am planning on trying differential thrust - it is going to have an Aura 5 that I pulled from a retired airframe.

That will be very interesting to watch.

Does the Aura 5 handles the yaw using the EDF's or do you need a Flight Controller? Normally, gyros handle only servos.

Hope you video it.

 

[danskis]

I put a center fin on 2 of my Versa Wings. Works great and looks cool. The further back it is the straighter it will fly.

 

[dap35]

That will be very interesting to watch.

Does the Aura 5 handles the yaw using the EDF's or do you need a Flight Controller? Normally, gyros handle only servos.

Hope you video it.

The Aura5 does have the ability to control yaw if you have two motors. This will be the first time I have tried it.

 

[dap35]

I am going to go with center fins. I have made several changes to the Spear. I will post some updates.

 

[L Edge]

Here are two new flying wings that don't exist that I designed to kick butt in high wings and gusty conditions. Flying wings are subjected to high alpha flying and really gusty conditions that can cause havoc. Also, landing on a runway in a crosswind with endplates is a problem.

So, to solve this, I designed the first wing with my own version "UDDER RUDDER" just in front of the prop so in essence, you have airflow at all times to handle crosswinds and the rest of the yaw problems. The only change I made is the transmitter rudder expo is negative, so small movements of the rudder stick give large movements of the rudder which work great when idle back for landing.
The rudder is in front of the prop and runs by a servo.

Both versions are flat plates(no airfoil) and weigh less than one pound!!!! The stabilizer(NACA designed) changes the airflow pattern across the wing that allows it to fly in all kinds of conditions. I left the endplates on so it can handle 20-30 mph winds and good landings on the runway.

So taking the endplates off, leave no vertical stabs on the wing.

This one weighs 419.3 grams and goes like a bat out of h--l and is designed for speed as well as going slow with a raised nose in real gusty conditions . Can be released(no slinging needed) downwind and at 2/3 throttle with no problem. If you want to see the videos flying in an enclosed area in good high winds and really gusty(all trees are 100+ where the wind has to come down and exit back up behind me) conditions, let me know.

Have over 100 flights on "udder rudder" and "no-vert" has about 40 on it. I have a 9 x 3/4 prop on it and a 2200 kv 3s motor. This spring I will reduce the prop size and it should do 100+ easily.

 

[dap35]

Pretty much finished with the build. I went with the center fins and differential thrust. Just need to get it balanced and find some good weather in a couple of weeks.

 

[dap35]

Finally a day with great weather. Today was maiden day my highly modified FT Spear. It flew great, 2 x 50mm EDF's were made for an easy hand launch. I still have to work on the differential thrust. It didn't do much for me, but it is possible that I had too much expo on the rudder control.

Video to follow later this week.

 

[L Edge]

Finally a day with great weather. Today was maiden day my highly modified FT Spear. It flew great, 2 x 50mm EDF's were made for an easy hand launch. I still have to work on the differential thrust. It didn't do much for me, but it is possible that I had too much expo on the rudder control.

Video to follow later this week.

Did you use reflex?

 

[dap35]

Did you use reflex?

Yes, I actually used the reflex guage from the kit. Video just uploaded..==> EDF Spear Maiden

 

[L Edge]

Yes, I actually used the reflex guage from the kit. Video just uploaded..==> EDF Spear Maiden

Takeoff and landing impressed me. You hit it right on the nail for setup.
So, you just push me into trying a flying wing with a 64mm EDF. Thanks!!!!

 

[dap35]

Takeoff and landing impressed me. You hit it right on the nail for setup.
So, you just push me into trying a flying wing with a 64mm EDF. Thanks!!!!

Using the Aura 5 makes for really easy hand launch.

 

[L Edge]

Finally a day with great weather. Today was maiden day my highly modified FT Spear. It flew great, 2 x 50mm EDF's were made for an easy hand launch. I still have to work on the differential thrust. It didn't do much for me, but it is possible that I had too much expo on the rudder control.

Video to follow later this week.

A good way to check out differential rudder is have a cross wind and try flying a straight line at an angle.
Or go up high and do a hammerhead.