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Oct 12, 2021, 04:58 PM
Flying What?!?
fnnwizard's Avatar

Prestige V-Tail FAI Light


I got a v-tail light and building it out. Not too extreme in the weight savings mods. I wanted to do a pull/torsion spring on the V's with the Armsoar pulleys on the servo, but I don't think I have time to implement it reliably. I need to get this done by next weekend.

Initial estimate for the various mass and will update as I move along.
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Oct 13, 2021, 05:36 AM
Registered User

Storm 2PK


New Storm in the house, now to get cracking. Full build ahead of me. Will be the first time installing IDS. Looks simple enough on the videos. Tape off everything, measure 3 times, cut it right the first time, glue it in.

R, E, Ail servos MKS HV6110
Flaps KST X10 minis
I have that set up in my standard 2PK and like it.

Going to try an Xpower Windy motor
Castle Talon 60 for ESC
3S Tattu 850 and 4S Tattu 650, may even try to fit a 3S 1300 for practice, if I can find one light enough.
CN 32mm spinner, with 11 x 6 or 7 prop.
Oct 13, 2021, 07:03 PM
Flying What?!?
fnnwizard's Avatar

Fuse and Vtail Linkage Details


I removed the ballast keeper in the fuse and dremeled out the portions of carbon that is not needed. Saved about 10g.

The Vtail horn as best as I could measure is right at 10mm in length, and the way it is mounted is equivalent to being canted aft ( towards TE) ~12°.

For ruddervator throws, I'm estimating about 20° of up and 25° of down and with more than 110 degrees of total servo throw available for the 6110 (the 6110 is actually capable of 120°+ on my Futaba radio, but the subtrim to make each servo mirror eats up about 5 in either direction). Give headroom of another 5 so I'll be using 105° of total servo throw which results in servo arm lengths @ 5mm.

There are challenges to using such short arm and my remedy is pictured. Simple and light. One can easily 3d print this keeper as a 1 piece. Just gotta cad it out.

I'm mounting the servos to my Rx and RX to the fuse either directly or via a plate secure via the ballast screw. Not sure yet, depends on the weight penalty vs serviceability.
Oct 14, 2021, 12:15 PM
Lover of fast slope gliders!
glasairIII's Avatar
This is going to be interesting.


Quote:
Originally Posted by fnnwizard
I removed the ballast keeper in the fuse and dremeled out the portions of carbon that is not needed. Saved about 10g.

The Vtail horn as best as I could measure is right at 10mm in length, and the way it is mounted is equivalent to being canted aft ( towards TE) ~12°.

For ruddervator throws, I'm estimating about 20° of up and 25° of down and with more than 110 degrees of total servo throw available for the 6110 (the 6110 is actually capable of 120°+ on my Futaba radio, but the subtrim to make each servo mirror eats up about 5 in either direction). Give headroom of another 5 so I'll be using 105° of total servo throw which results in servo arm lengths @ 5mm.

There are challenges to using such short arm and my remedy is pictured. Simple and light. One can easily 3d print this keeper as a 1 piece. Just gotta cad it out.

I'm mounting the servos to my Rx and RX to the fuse either directly or via a plate secure via the ballast screw. Not sure yet, depends on the weight penalty vs serviceability.
Oct 15, 2021, 07:30 PM
Flying What?!?
fnnwizard's Avatar
Well, while the debate rages on in my head about how I should mount the Rx and Sx, figured I would finish out the Ail.

I'm using the stock g10 Ail horns and modified it to sit more forward. This results in the horn length being about 9mm. I only need +-16° of Ail throw so that makes ideal servo arm length just 3mm but the minimum I can do is ~4.6mm, see the servo arm hole. It's right up against the splined hub.

I'll have to cut down the ail servo endpoints to just+- 33°. That's using just 55% of available throw, The arms should be biased ~9° aft but it's not that critical since I still have plenty of throw leftover to use.

I can't imagine using ids on the ail of this thing.

Anyway, the servo ( leads shorten by 80mm, saved 1.5g, lol, it's more for wire management)) will be shoogoo'd into place with its bottom and side glued directly to servo box and the mounting tab butted up against the rear. This gives room for the servo wire to move in and out when connecting to the center panel. Also keeps the the linkage as short as possible.

The L bends for the control rods were a bit hard for me to do. I used some hardened SS and kept snapping it. Had to make the bends really slow , but I did finally get lucky to get a set exactly the same size without having to get out the torch.

This all results in as minimal added weight to the tips as possible. Waiting for the glue to dry and back to debating with myself about the 10g added for fuse rx/sx tray.

Ps, center panel I'm doing ids and there's really nothing to mod on it so likely won't post anything regarding that. I'm aiming for 114 cg on this and have cut off 25mm of the nose already.
Oct 15, 2021, 09:26 PM
Lover of fast slope gliders!
glasairIII's Avatar
She’s a pretty one.

Quote:
Originally Posted by dodgeit
New Storm in the house, now to get cracking. Full build ahead of me. Will be the first time installing IDS. Looks simple enough on the videos. Tape off everything, measure 3 times, cut it right the first time, glue it in.

R, E, Ail servos MKS HV6110
Flaps KST X10 minis
I have that set up in my standard 2PK and like it.

Going to try an Xpower Windy motor
Castle Talon 60 for ESC
3S Tattu 850 and 4S Tattu 650, may even try to fit a 3S 1300 for practice, if I can find one light enough.
CN 32mm spinner, with 11 x 6 or 7 prop.
Oct 16, 2021, 08:06 PM
Registered User
Quote:
Originally Posted by glasairIII
She’s a pretty one.
Thanks!! Fuselage servos in and adjusted, Both Aileron IDS are in including servos. Flaps IDS with servos are next. This is my first attempt at installing IDS. So far it is going well, but slow.
Oct 17, 2021, 03:57 PM
Flying What?!?
fnnwizard's Avatar
Quote:
Originally Posted by dodgeit
Thanks!! Fuselage servos in and adjusted, Both Aileron IDS are in including servos. Flaps IDS with servos are next. This is my first attempt at installing IDS. So far it is going well, but slow.
That is a gorgeous looking beauty Dodgeit! Would you happen to have any component weights handy?

Here are some details to my motor system with down thrust. I find down thrust to be needed for the normal model if you want to dash fast at level attitude. It's 1mm the bottom edge of the spacer.

I'm using a drone ESC, XT 30 connector. The whole assembly weighs 119.6g
Oct 18, 2021, 11:10 AM
Registered User
Quote:
Originally Posted by fnnwizard
That is a gorgeous looking beauty Dodgeit! Would you happen to have any component weights handy?
Thanks for sharing the motor information.

wing tips 180g each
wing center 663g
fuse 172g
nose 63g
elev 36g
rud 44g

Total 1338grams, Bare airframe, nothing installed, not even the joiners.
Oct 23, 2021, 02:52 AM
Flying What?!?
fnnwizard's Avatar
Quote:
Originally Posted by fnnwizard
Well, while the debate rages on in my head about how I should mount the Rx and Sx, figured I would finish out the Ail.
Ok, so serviceability over absolute minimal weight ended up winning over and this is the ending result to the servo tray.

I used the ballast hole with a 5mm screw as one of the anchor points and made another hole in the pod for a 4mm screw.

Close observation of the tray should answer all questions.

I also finished sanding down the nose to better mate with the spinner to fuse from the added downthrust angle.

I was targeting 114mm for cg with 50mm of the nose cut off and it came out at 113.1 with a rtf mass of 1139. However that is without the taped on tail piece. I had forgotten all about it and haven't weighed it yet with the tail piece.
Last edited by fnnwizard; Oct 23, 2021 at 02:58 AM.
Oct 23, 2021, 03:27 AM
Flying What?!?
fnnwizard's Avatar
Almost forgot...
The stock teflon sheaths supporting the pushrods end right near the rear wing screw.
For anyone wanting to move the servos forward, another sheath for support must be made.

For me, I added an etched teflon piece that extends from 1" forward of the existing one to 1" of the L bend rods.

I'll be adding the flap install details also when I have time. I wasn't going to do it thinking it should be easy and common knowledge since IDS is so prevalent, but because the FLAP horn is so short, the install becomes much more critical to get right.

Even though our speeds are relatively slow, there is a lot of force pushing on the pushrod and if the geometry isn't good, that pushing is directed towards the hinge, trying to peel it from the flaps vs a more favorable shearing force.
Oct 23, 2021, 12:03 PM
Registered User
Tuan: What speed controller are you using?
Oct 23, 2021, 01:28 PM
Flying What?!?
fnnwizard's Avatar
Quote:
Originally Posted by beach1
Tuan: What speed controller are you using?
I'm using a drone esc by Holybro with the metal fets.
http://www.holybro.com/product/tekko...metal-esc-65a/.

Drawing rx power from 2 out of 4s.
Oct 28, 2021, 10:59 PM
Flying What?!?
fnnwizard's Avatar

Latest Mods


Got a second session of tuning today and I had to make some changes.
Was at 113.3 mm cg and it felt a bit nose heavy.

The following changes were done after today's session.

Vtail ele is currently maxed out and was touching each other7 so I sanded the corners to clear.

At 40oz, she can make such a tight circle that the pitch rate is very high. Stock factory ele throw is not enough.

Few things to help ele...

Move CG back, chop off tail piece and chop off more of the nose.

After cutting the tail piece, I was able to cut another 27mm off the nose and it's currently 310mm long.

Cg is still ~113, and overall savings is 9.1g ( cutoff tail piece + 30mm of nose piece)

Anyway, no more time to make any changes, tuning flight tomorrow and contest this weekend.

Will report back how she does.
Nov 03, 2021, 04:59 PM
Flying What?!?
fnnwizard's Avatar
More Data.
Ok, I remeasured CG to get a more accurate reading. I flew in a contest this past weekend and used the ~40oz V-tail for Rds 1,2,7,8,9,10.
CG for Rds: 1,2,7 was @ 114.6mm. AUW = 1123g
CG for Rds 8,9,10 was @ 122.6mm with 8.7 grams of lead taped to the tail making AUW 1133g. ( the extra 1.3g could be error from cg machine resolution)

Sat eve, at cg=114.6, the wind was finally calm enough to get in a trim flight, log attached. At ground level the wind was barely noticeable, but at 100m up, I was flying "backwards" with 5° of camber. Sink speed = .14m/s.

It was getting dark fast and getting hard to see the plane, so I flip the switch to reflex (-1°) and Vtail would slowly come back to me with sink speed = .26m/s.

As it approached over head, I toggled between cruise and T2 and she stayed pretty much in the same location relative to the ground with sink speed at .19m/s.

I have no idea what the wind speeds were relative to the altitude.

Rd 10 log has to do with sink speed against a stiff wind. At this point the CG is 122.6mm. Sorry no wind data, but in this flight, on 3 occasions was at the limits of my vision downwind. In hindsight, I should have flown 45oz Prestige.

The graph shows 3 peaks. With the 3 times I reflexed back home to keep her in sight.

The 2nd peak I actually lost sight for a bit, but kept holding a bit of down ele until I thought she was in sight, bring back stick to center and and you can see the immediate pitch up.

The last peak shows me scooting home, much faster than I needed to since I traded all the altitude to be able to pick up the next thermal. This was a 15 min rd and I was short 5 min.

Anyhow, 2 big things learned. CG still too stable for my liking at 122.6mm. I think it can go back to 125-126 and be better.

Don't need to fly so fast to get back home.


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