The Mongrel Project.

[SSgt Duramax]

I like this, I am working on something a little the same, but a little different. Mine is going to have one 2212 motor and twin CF arrow booms. 60 inch wing span and a 4 inch chord (high aspect ratio). I think I might need a mulligan on the fuselage, as my design goals have changed slightly.

 

[Beaver5150]

we have a similar problem, but not quite so bad. but i'm uncomfortable above 6mph steady, and hate gusts.

big gusts have blown my models beyond sight, or into trees. i have to be careful with my madness

Th

I like this, I am working on something a little the same, but a little different. Mine is going to have one 2212 motor and twin CF arrow booms. 60 inch wing span and a 4 inch chord (high aspect ratio). I think I might need a mulligan on the fuselage, as my design goals have changed slightly.

I like it.... twin booms, I did that on my first plane I built a couple years ago... out of cardboard and dowell rods. Flew it hard for a month before I killed it. I've had good luck with 2212s, 950 to 1300kv on 3S.

 

[Beaver5150]

I use flight controllers now, so the wind isn't as much of a problem as long as I have plenty of power..... up to a point.

 

[Beaver5150]

Afterthoughts on the last Mongrel sessions and somewhat related to recent experiences with my "Stinger" tri-copter as far as power systems, motors, props, volts, weight, etc..... I'm thinking very seriously about going with the twin 2812/950kv motors (with 9x5 props on 3s) left over from when I recently re-motored Stinger. They were actually more efficient for flight time compared to the 7 inch setup I have now..... and they were quiet! I can fly Stinger up to around 11pm and had no complaints even on the noisier 7 inch setup, but I don't want to push it too far past that. The goal is to have Mongrel fly at night, be stealthy-quiet, and be a testbed for the "1 hour flight" challenge someone put on me recently when I pulled a 20 min flight out of a 41" Extra-330S on a 3s/3600mAh (simple throttle management actually).
As far as flying at night is concerned, I nailed it with Stinger..... all good...... I'm still contemplating the lighting for Mongrel. But I'll nail it in a minute.
Btw...... Suggestions welcome!

 

[Beaver5150]

we have a similar problem, but not quite so bad. but i'm uncomfortable above 6mph steady, and hate gusts.

big gusts have blown my models beyond sight, or into trees. i have to be careful with my madness

Okay, a few recent posts have been out of sync. My apologies. (New smartphone)

Flight controllers help tremendously in dealing with the wind. I've even successfully used helicopter controllers like Brain/iKon and V-Bar. I almost used an iKon for Mongrel, but used the Aura5 since it was already set up for my 330s, plug and play. Auto-level was active during all of the flights. It holds level until I make it do otherwise, even in the wind. Somewhere in a video, there was a point where I was going to do a loop and forgot to turn level off. That was awkward for a few seconds.

 

[Beaver5150]

Things are improving after some minor "after crash" structural reinforcements from the tree incident, mainly anchoring the tail surfaces more permanently and removing the extra elevator surface I added before..... didn't need it after all.
I also spent more time flying with gyros off so I can get an actual feel for the plane instead of the gyro masking bad trims.... adjustments made.
I installed a 2812/950Kv motor and 9x5 prop with sufficient results. I will make a few more flights in this configuration before I decide if I want to go with twin 2812s.
I'm waiting for a 3S/5200mAh/50C pack and a set of 3 inch superlight landing wheels to show up in the mail next day or two.
I want Mongrel to sit like a bush-plane and jump off the ground like one too!
Wait... am I trimming a plane or training a dog?

 

[Beaver5150]

What started as a quick test flight with the new 3S/5200mAh and a used 2212/950kv motor and 8x5 prop turned into a 10 minute "bucket list" flight, as a couple of stork/heron looking birds of near same size as Mongrel, ventured into my airspace around 4 minutes in.
They circled in as if to see what I (it) was, and then I turned in with them and ended up flying in formation with them, for at least a solid minute before they started going out of my airspace, then I peeled-off and came back toward home. The wind was around 13-15, and at moments, all 3 of us were just hangin-out, hovering in mid air. I built Mongrel just for that sort of flying, so I (we) were right in the groove with it. ("We" because the plane is an extension of myself when flying)

You just don't see perfect moments like that very often.
Shame I didn't have a camera going!

 

[Beaver5150]

Mongrel is down.
I put all 3 2807/1700Kv drone motors on with the matching 7x4.5x3 props, and things were going perfect. It was flying in a 30mph wind holding stationary in the air at less than 1/4 throttle, took off straight up like a rocket within a 1ft roll as I expected. I did notice the wing flapping a bit due to turbulence, but figured it would hold up.
I landed and went in to grab a camera and tripod, then made a second attempt that ended up in the wing folding first time I did a hard turn to get back into the camera frame. SNAP!

Frame is mostly intact, but the front section where the Lipo would normally sit is trashed as are the freshly made motor mounts on the dead wing. I haven't checked any of the electronics yet.
I haven't made up my mind whether or not to rebuild yet.

 

[Beaver5150]

Okay... Now that I've had a day or two to "cool off" after having both Mongrel and Stinger go down on two consecutive days, I finally took a good look at things. I can probably get around the frame damage it Is employ some foamboard in the right places. Otherwise I will have to look for a Blade 450-3D helicopter main frame to replace the original one that actually did have minor damage when I bought it from the RC-Groups classifieds. If I augment the existing damaged frame, I will probably build forward to allow for forward CG bias, as well as lengthening the tail boom a few inches to get a better CG setup when running "big mAh-packs" for the 1-hour challenge".
I was impressed with the 2 short flights I got in with the "tri-motor" setup with the 2807 motors before the wing folded. Stinger shot up like a rocket at 2lbs with 2807s, Mongrel weighs about the same so I expected the same. I was right on that point! Watch for the video....
Here's the frame damage....

 

[Beaver5150]

While working the rebuild strategies for Mongrel-Mk2, I discovered a cleaner way to mount the center motor using carbon fiber tube and motor mount block from a 250 quad. I should even be able to add some rubber bits for noise isolation, as I'd like to make Mongrel stealthy for low speed night flying. The next wing pylons/nacelles I fabricate will also be isolated if possible.

To the wing...
Last one, I put the 1"x1/4"x36" spars in flat instead of standing up. I intend to significantly increase the aspect ratio, so 2 spars oriented through the stiffer 1" section plus whatever else I add, should make the wing significantly stronger. On a 10" chord, 1"+another 1/2" for foamboard, should be around 15% aspect ratio.
I'm going for 800 to 1000 sq-in in prep for running over 12,000mAh worth of LiPo at a FUW of close to 56oz. I want the wing loading down to "gliderish" specs Like it has been.
I'll upload the video of the last take-off when the thing practically jumped off the ground. It's the one reason I want to keep the 3-motor setup.

 

[FlamingRCAirplanes]

Nice!

 

[Beaver5150]

Hardware mode engaged....
Marathon rebuild session in progress, I'm not stopping till it's done..... that's how I roll (or fly... whatever)
Will still be 3 motor... tail boom stretched by 6" already, fuselage currently being expanded to enclose all 12,200mAh worth of LiPo I intend to carry. Wing (or wings) to be built after frame finalized.
Here's the video from the 3-motor test, the 2807/1700Kv's with 7" props and at least 3000g static thrust on a 1000g plane. Listen for the wing to snap off screen just before end of video. (It's noisy from the 30mph wind)

 

[Beaver5150]

Well, I made progress on the fuselage/tail assembly. There's plenty of room to hold/move Lipo's around to set CG. Given the wingspan, I figured I can afford to widen the fuselage to accommodate extra batteries and still not be disproportionately wide.
I'm done for the night (morning)........

 

[Baron VonHelton]

Hardware mode engaged....
Marathon rebuild session in progress, I'm not stopping till it's done..... that's how I roll (or fly... whatever)
Will still be 3 motor... tail boom stretched by 6" already, fuselage currently being expanded to enclose all 12,200mAh worth of LiPo I intend to carry. Wing (or wings) to be built after frame finalized.
Here's the video from the 3-motor test, the 2807/1700Kv's with 7" props and at least 3000g static thrust on a 1000g plane. Listen for the wing to snap off screen just before end of video. (It's noisy from the 30mph wind)

"Nothing above a 5mph wind for FT aircraft"
- Josh Bixler

 

[Beaver5150]

"Nothing above a 5mph wind for FT aircraft"
- Josh Bixler

That's funny. I flew a FT Explorer with a 60" (600sq-in) in 10-20mph wind frequently, after the original wing snapped.

 

[Beaver5150]

It's not going as quickly as I had hoped, but the rebuild itself is coming along nicely after another long session. The new wing is nearly complete, up from 570sq to 690sq-in, with around a 10% aspect ratio. It took me a few days to finally settle on a wing profile and what to use for motor mounts. They ended up being plastic bits I modified from dead printer/scanner parts (paper guide).
The wing motors are mounted and run-up tested. I have yet to make some "faux-nacelle" covers top and bottom so most of the esc and wiring will be hidden as well as being ducted for cooling.

There are a few more small structural issues to work out next session, but all minor details (wing to tail boom bracing, etc).
I'm rerouting the wiring and adding a few connectors to make things more modular in case I decide to remove the pusher motor.
I may add a 5A UBEC to the mix, as I noticed the BEC in the center ESC is only 2A, and I will be adding more equipment as I go. The fuselage is now 4" wide, plenty of room for Lipos and electronics.
I'll eventually scratch build a canopy shell for the front, with camera mount, lights, etc.

I should have this thing ready to re-maiden as Mongrel Mk-2 before the week is up.

 

[Beaver5150]

I thought I was going to get a test flight in this morning, Mongrel almost ready, till it started raining. Go figure.

 

[L Edge]

First of all, how in the heck did you come up with the idea of using old heli parts?
I was impressed with that flight you took.

Some suggestions for your 1 hr challenge flight.
With your center motor/prop only, 2 tricks you may try to decrease drag(less wattage, longer flight time) is to:
1) change the angle of attack of the wing( plus or minus) a couple of degrees
2) change the angle of the center motor a couple of degrees (assuming you can change the length of the 2 arms) to see if the force vector will add to your flight time or hinder you.
3) get rid of all that extra weight
4) To improve your flying in the wind, learn to rely on the rudder in the turns to help you. And always, never fly downwind of you, keep that plane upwind(what happens if the motor quits) at all times and use that rudder to get you around to land.

 

[Beaver5150]

First of all, how in the heck did you come up with the idea of using old heli parts?
I was impressed with that flight you took.

Some suggestions for your 1 hr challenge flight.
With your center motor/prop only, 2 tricks you may try to decrease drag(less wattage, longer flight time) is to:
1) change the angle of attack of the wing( plus or minus) a couple of degrees
2) change the angle of the center motor a couple of degrees (assuming you can change the length of the 2 arms) to see if the force vector will add to your flight time or hinder you.
3) get rid of all that extra weight
4) To improve your flying in the wind, learn to rely on the rudder in the turns to help you. And always, never fly downwind of you, keep that plane upwind(what happens if the motor quits) at all times and use that rudder to get you around to land.

Thanks for the suggestions.

The helicopter frame idea is actually the second time I've employed the use of a helicopter boom and frame, but only segments tied into another frame. (See Stinger Front Steering Tri-copter in thread list). I just happened to decide to use a whole frame for a plane while plotting this build. I attempted the tail surfaces to tail boom first, then while figuring a tie-in to a frame, decided to use the rest of the heli frame itself.
The one I used is unserviceable as a heli frame.
I have another heli frame to restore anyway.

I'm 3 flights in now with this thing up and running again. I did have to adjust the incident angle as it wasn't near +9° as I thought it was (wing).

I had already planned on trying different motor configurations among the 3, different props, different packs, and logging the results.

As for flying in the wind, this latest video (today) is what I intended the day the last wing folded.
Watch for the landing.

 

[Beaver5150]

Okay. Mongrel is back.
Now that it's reasonably well tested and trimmed, I can get back to simply flying the thing for awhile before I make any more modifications.
Wing is up to 720 sq-in, from 570.
Still using 3-motor setup, and the tail boom was stretched by 6 inch for better stability and tail authority.