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Sep 10, 2014, 08:34 PM
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Nice Hawk


Hey John,
That plane looks great!!!
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Feb 13, 2015, 10:42 AM
Fort Worth Thunderbirds
Sunbyrd's Avatar

Boxjet


Well, it's been a year since I scratch built the MiG Stick. Here's what I've got on the bench now. It doesn't look like much yet, but it's going to be an 90mm EDF trainer with a 59" wingspan. My goal is to have it's flying weight around/under 7lbs. Which will give it a wing loading of around 30oz/sqft.

I'm going to use the 90mm, 1750 watt RC Lander EDF unit that came out of my Nitro Planes Fan Trainer.

I've abandoned the Fan Trainer because it was just a very poor design. Took all the usable hardware out for this project. The problem with the Fan Trainer was that the horizontal stabilizer had negative incidence which caused the plane to porpoise a lot. The main landing gear was too far forward so it was difficult to keep the nose wheel on the ground when taking-off. And if that wasn't enough, it had a 39oz/sqft wing loading. These problems were just plain too difficult to correct, so adios!

If the weight of my trainer does come in around 7lbs, it should give me a wing loading more similar to a warbird. The RC Lander EDF should then give me about 250 watts per pound. It had plenty of power to push the Fan Trainer through the air, so it should have enough power for this plane with its lighter wing loading.

I would welcome any thoughts or comments.

P.S. If anyone can come up with a better name than "Boxjet" let me know...
Feb 21, 2015, 08:42 AM
Fort Worth Thunderbirds
Sunbyrd's Avatar

Boxjet Progress 2/21/15


Here's some pictures of the progress on the scratchbuilt. The nose is starting to look more like an airplane than a boat now. Pretty much the same layout I used for the Migstick. All open in front to allow lots of air to flow through the fuselage.

Check out the batteries. Thanks to Gary Rife for turning me on to the Glacier Lipos. Both of the batteries in the picture are 5000mAh, 6 cell batteries. Check out how much smaller the Glacier is than the Zippy. I haven't actually weighed them but the Glacier feels to be a couple of ounces lighter than the Zippy although it is about an inch longer than the Zippy. They are both 45C discharge but the Glacier claims a 5C charge rate...if I understand it correctly, that would be 25 amps???? That really seems like a lot.

The second picture shows what the Glacier looks like laying in the battery tray.

The third picture shows the wire tunnel and vertical stab support. The trapazoid shaped things are mounts for the horizontal stabs that will raise the elevators out of the wing's wind shadow(??? turbulence from the shoulder mounted wing) and give them a good bit of positive dihedral. It will also serve as a space to mount the rudder servo.

The last picture shows the unfinished side air intakes.

Anyone think of a better name than "Boxjet" yet? I'm still open to suggestions but Boxjet is growing on me.
Mar 05, 2015, 07:41 AM
Fort Worth Thunderbirds
Sunbyrd's Avatar

03/03/15 Boxjet Progress


Starting to look like an airplane...sorta
Last edited by Sunbyrd; Mar 05, 2015 at 07:58 AM.
Mar 06, 2015, 01:26 AM
Registered User
rowdyjoe's Avatar
Very nice. Are you going to paint it or cover it?
Mar 06, 2015, 06:56 AM
Fort Worth Thunderbirds
Sunbyrd's Avatar

Boxjet


I'm planning on covering it with Ultracote or similar light weight covering in a splinter camo pattern. (something like in the pictures) I've never done a camo job in film and with the all solid structure it should be fairly easy. Also, since this plane is all angles, I think the splinter pattern camo is more fitting. Just from Googling images, it looks like the U.S., Russia and many European aircraft sport this sort of pattern.
Mar 06, 2015, 03:31 PM
Registered User
rowdyjoe's Avatar
That will look very cool.
I don't know if my old eyes could track that camo in flight. I have trouble with the ME 262 on a cloudy day.
Apr 24, 2015, 11:05 AM
Fort Worth Thunderbirds
Sunbyrd's Avatar

Boxjet 4/24/15


I think it's ready to fly. Hope I haven't forgotten anything. The final weight ended up being 7.9 lbs. Wing loading should be 33oz/SqFt. That should give me about 221Watts/lbs at full throttle.

Just need a favorable weather day now.

Update: Maidened the Boxjet Saturday nooonish, May 2nd. Winds were about 8-10 mph from the south, right down the runway. Taxied out and throttled up gently. About a third of the runway pulled it up gently and it lifted off easily. Gentle climbing turn to the left, then at altitude a couple of clicks up and a couple of clicks of left trim and it was flying hands-off. Airplane was very stable and predictable. Able to cruise at half throttle easily without losing altitude. Tried out a roll on that first flight. The way it flies, it's hard to believe it's an eight pound airplane with a 33oz/sqft wing loading. Had the timer set for three minutes for the first flight. Landed without incident and checked the battery. Cells were down to about 3.82 volts per cell.

For the second flight, went high rate for the ailerons and the roll was a bit more crisp. It pulls up through a loop from level flight with no problem. Did a split S, also without any problem. Second flight lasted three and half minutes and battery was down to 3.7 volts per cell.

I couldn't be happier with the way this airplane flies and lands. It pretty much proves that 200 watts/pound works well for an EDF.

Thanks to Roddy Lowrie for the moral support and extra hands in case it was a handful on the maiden flight.
Last edited by Sunbyrd; May 03, 2015 at 10:39 PM. Reason: Maidened the Boxjet
Apr 25, 2015, 06:23 PM
Registered User
rowdyjoe's Avatar
Looks good. I see you gave it a bit of attitude. You were right about the "camo" scheme. It does break up the angles very well.
Don't forget to post a flight review and a video would be great.
May 13, 2015, 12:09 PM
Registered User
After a couple of years hangar queening........I think Im actually finishing it this time.
May 13, 2015, 12:38 PM
Fort Worth Thunderbirds
Sunbyrd's Avatar
Wow...that's impressive. What are the specs and details? Can't wait to see that fly.
May 13, 2015, 04:29 PM
Registered User
Its 1/7th scale, I think like 64" wingspan and about 85" long. Its big. I think it will weigh about 35-40lbs with fuel.
Not happy with the colors. Once I fly it I will very likely repaint in.

Got it 3 years ago, started it, then moved within FW so I boxed it up and just recently got the engine for it so here we go....
May 16, 2015, 02:27 PM
Registered User
...
Last edited by Terry Thorpe; Aug 21, 2015 at 03:34 PM.
Aug 19, 2015, 08:07 AM
Registered User
Does anybody, preferably on the west or north side of FTW, have a postal scale I could use? I'm about to switch from film to paint on a model, and I'd like to be able to measure the weight change.
Aug 21, 2015, 01:13 PM
Registered User
The F-35 flew.......still in the process of trimming and learning it. Kind of a handful, but its a sweetheart at low speeds.

FEJ F-35 Maiden (3 min 8 sec)


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