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Sep 10, 2019, 06:26 PM
Retired CAD guy
birdofplay's Avatar
Well , since the MPF foam seems to be slightly thinner I wouldn't expect things to get heavier
with a couple more thickness's.
Actually I'd expect a Lighter version given the whole wing will be slightly thinner.

Is the 250g limit one of those Hard points for legality ?

I'll be flying at my place almost exclusively so I really don't worry about the weight much.

I just added a dimensional screen shot with 16 6mm squares across the big foam plate. and dimensions.
Last edited by birdofplay; Sep 10, 2019 at 06:33 PM.
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Sep 10, 2019, 07:47 PM
Registered User
Thread OP
Quote:
Originally Posted by birdofplay
Well , since the MPF foam seems to be slightly thinner I wouldn't expect things to get heavier
with a couple more thickness's.
Actually I'd expect a Lighter version given the whole wing will be slightly thinner.

Is the 250g limit one of those Hard points for legality ?

I'll be flying at my place almost exclusively so I really don't worry about the weight much.

I just added a dimensional screen shot with 16 6mm squares across the big foam plate. and dimensions.
I'm wondering on this big foam plate? I didn't understand it at first, but I'm wondering if my PDF somehow lost it's text. There is an info plate on the bottom right of my main page which lists the info for the model, but it's not intended to be a piece to cutout. On your plans though it looks very similar. Or is this a mod you are doing?

Yes, 250g is a legality issue in a number of countries. RcGroups tells me you are in the USA so it probably only matters to you for registration requirements.

However, in Canada to fly a craft over 250g you need:
  • A License
  • Registration number for each aircraft ($5 each)
  • Logbook of all flights
  • Logbook of all maintenance
  • Can't fly in controlled airspace (so pretty much no flying in any major city) unless you have an approved model (which scratch-builds sure aren't) and then you still need to contact ATC for approval
  • Site survey
  • Spotter for FPV
  • Etc.

It's similar in a number of other countries like GB and Australia, I believe.

Does it matter? Certainly not if you fly out on your private property. Not like anyone really cares, or local cops are likely to know the full rules. However, if some incident ever did happen, or someone reports your video on Youtube (I know some popular youtubers have had this happen), with sub 250g the main regulations do not apply to you and thus you can't get fined for anything.
Sep 10, 2019, 08:03 PM
Retired CAD guy
birdofplay's Avatar
my comments re UAVing are here

https://www.rcgroups.com/forums/show...ostcount=11225

what we really need is MORE govt intervention in our Happy fun Times ! sigh ........
Sep 10, 2019, 08:11 PM
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Quote:
Originally Posted by birdofplay
notamedclosed:

Could we have some closeups of you motor installation , Please ?

Is the TE of the FUSE a DownThrust angle for the motor to be mounted flush against ?

What prop are you using ?
I assume something like an AVAN 3 2.4 3 blade .
But I am open to suggestions :^}

LIPO is a 2s or 3s or 4s 850maH pak ? correct ?
All components were listed on the youtube video, but maybe I should add them in here as well. I also realized I also didn't have a link to the thingiverse page for the motor mount.
https://www.thingiverse.com/thing:3843730

Lipo is 3S or 4S 650mah 75C Tattu.

Props are HQ Durables Tri T3x3. I think those AVAN props may be problematic to mount as a pusher. The bell gets in the way of that big swoop.

There is no angle on the motor mount. Might be worth adding one, flies great as is but the FC is probably compensating.

I don't seem to have a picture of the current mount, just the V1 which was designed to make the motor removable. I'm on the road right now but I'll try to get a refreshed picture. Once you have the 3d mount I think it's fairly obvious though. The V2 mount attaches to the motor directly and glues in for weight savings.

Oct 02, 2019, 09:09 PM
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CrashAndBash's Avatar
I stumbled on this design & I am liking what I see. I am just building a twin engine Inav FT dart using RCINPOWER GTS V2 1207 5000 KV motors. Once I destroy that I thought I'd use one of the motors and build this.

Still debating whether to use depron or EPP. Depron stiff but brittle. 5 mm epp floppy but very resilient. Which would you suggest? I am thinking a hybrid approach - EPP for the nose & depron for the wings etc.

Be interested if you come up with any updates. Please keep us posted.
Last edited by CrashAndBash; Oct 03, 2019 at 01:29 AM.
Oct 02, 2019, 09:54 PM
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Quote:
Originally Posted by CrashAndBash
I stumbled on this design & I am liking what I see. I am just building a twin engine Inav FT dart using 1206 5000 KV motors. Once I destroy that I thought I'd use one of the motors and build this.

Still debating whether to use depron or EPP. Depron stiff but brittle. 5 mm epp floppy but very resilient. Which would you suggest? I am thinking a hybrid approach - EPP for the nose & depron for the wings etc.

Be interested if you come up with any updates. Please keep us posted.
Depends how much you plan to crash of course .

A hybrid approach could work well. The wing has already survived some damage including a pretty high speed hit on a soccer gate. So far no damage to the fuse except for the hatch tearing off. The vertical stabs break the most.

I'm still flying it regularly but I am also working on a new KFM4 version with only a 600mm span.
Oct 03, 2019, 01:41 AM
Registered User
CrashAndBash's Avatar
Please post your new design when it becomes available.

I crash a lot btw. I typically fly 1-2 metres above the ground around trees and other obstacles, goal posts etc trying to fly the same path as I do with my 3" quads. So I do prefer laminated EPP. I really only use inav for the OSD including the GPS speed as at very low heights failsafe with RTH is far worse than simply cutting all power and dropping.


Quote:
Originally Posted by notamedclosed
Depends how much you plan to crash of course .

A hybrid approach could work well. The wing has already survived some damage including a pretty high speed hit on a soccer gate. So far no damage to the fuse except for the hatch tearing off. The vertical stabs break the most.

I'm still flying it regularly but I am also working on a new KFM4 version with only a 600mm span.
Oct 21, 2019, 12:46 PM
Registered User
REPOSTING here in case anyone has had similar problems:

So, we had a great 18C wind free day yesterday so was able to get out with for some more test flights on my modified Foamtini but didn't have much success. I had adjusted the FC's pitch setting by 5 degrees or so but it didn't make any difference and the porpoising was still really bad most of the time. I had one flight where it flew fairly well for four minutes on 3d cruize mode but then it started to porpoise again. It didn't seem to matter what flight mode I was in as it did the same thing on horizon and even a bit on autolaunch. I was thinking it had something to do with an iNav setting somewhere but then discovered the porpoising also happens in manual mode! This means that the FC and iNav is really not the cause of the problem but rather that it's something physical on the plane. The pitch axis oscillations are at about 60hz (should check the iNav blackbox to confirm if it was working) and don't seem to be speed or throttle related. The servo links are pretty tight (as tight as all my other planes), the pushrods are as thick as on my similarly sized planes, and the elevons are Monokote covered balsa so are very stiff. The only thing that I think could be flexing is the wing itself but it seems almost as stiff as my other sub 250g plane - just a bit less because of the KF airfoil.
Any ideas what could be causing this and what I might try to fix it? I could upload a flight video if that would help. When the plane was not porpoising, it flew really well and climbed like crazy so I'm hoping I can figure it out before the end of the flying season here. Any suggestions or tips would be appreciated. Thanks!
Oct 21, 2019, 01:40 PM
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Thread OP
Quote:
Originally Posted by nlodoen
REPOSTING here in case anyone has had similar problems:

So, we had a great 18C wind free day yesterday so was able to get out with for some more test flights on my modified Foamtini but didn't have much success. I had adjusted the FC's pitch setting by 5 degrees or so but it didn't make any difference and the porpoising was still really bad most of the time. I had one flight where it flew fairly well for four minutes on 3d cruize mode but then it started to porpoise again. It didn't seem to matter what flight mode I was in as it did the same thing on horizon and even a bit on autolaunch. I was thinking it had something to do with an iNav setting somewhere but then discovered the porpoising also happens in manual mode! This means that the FC and iNav is really not the cause of the problem but rather that it's something physical on the plane. The pitch axis oscillations are at about 60hz (should check the iNav blackbox to confirm if it was working) and don't seem to be speed or throttle related. The servo links are pretty tight (as tight as all my other planes), the pushrods are as thick as on my similarly sized planes, and the elevons are Monokote covered balsa so are very stiff. The only thing that I think could be flexing is the wing itself but it seems almost as stiff as my other sub 250g plane - just a bit less because of the KF airfoil.
Any ideas what could be causing this and what I might try to fix it? I could upload a flight video if that would help. When the plane was not porpoising, it flew really well and climbed like crazy so I'm hoping I can figure it out before the end of the flying season here. Any suggestions or tips would be appreciated. Thanks!
Definitely post some video. Oscillations not related to speed seem very weird. Almost anything that I can think of which would cause them would change with speed.

Can you shift your CG forward and test that?
Oct 22, 2019, 09:07 PM
Registered User
Crossposting here from the Canadian thread. Here's a short video showing the oscillations in Autolaunch, horizon and manual modes (thus likely not iNav induced). Any suggestions?

Foamtini oscillations (1 min 3 sec)
Nov 09, 2019, 06:55 PM
Registered User
Thread OP
I was trying to test out the V2 Tarsier lens but ended flying other planes too long so it got dark. FPV feed still looks good though, so here is an uninterrupted flight.

Foamtini - Night Flight (6 min 11 sec)
Nov 13, 2019, 01:41 PM
Registered User
Thread OP
FoamTini - Emergency Landing! (3 min 54 sec)
Nov 25, 2019, 10:51 PM
Registered User
Thread OP
FoamTini - White Out (1 min 39 sec)
Dec 24, 2019, 08:46 AM
Build, crash...repeat
AleRRon's Avatar
Hereís my version. I liked the idea of a small FPV wing for learning how to fly FPV. I used DTFB covered with colored packing tape on one side and I built a box fuse with a little different shape. It weight about 218 grams fresh but after a crash and some glue and tape repairs it might be a little more now. Anyway, itís a great little flier. Very fast using an 1806 2250 kV motor and 3S lipo. I burned out two 1407 3500 kV motors on it at first. Not sure why but I think the 4.5 props recommended for the motors was too much. No problem with the 1806 and 4.5 APC prop.
Dec 24, 2019, 11:47 AM
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Thread OP
Quote:
Originally Posted by AleRRon
Hereís my version. I liked the idea of a small FPV wing for learning how to fly FPV. I used DTFB covered with colored packing tape on one side and I built a box fuse with a little different shape. It weight about 218 grams fresh but after a crash and some glue and tape repairs it might be a little more now. Anyway, itís a great little flier. Very fast using an 1806 2250 kV motor and 3S lipo. I burned out two 1407 3500 kV motors on it at first. Not sure why but I think the 4.5 props recommended for the motors was too much. No problem with the 1806 and 4.5 APC prop.
Looks good! Do you have an FPV camera on there yet?


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