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Posted by Old_Pilot | Nov 22, 2020 @ 02:18 PM | 4,531 Views
Hawker Tempest Mk-1 Foamie

I got the airframe cut out this morning, with the exception of the firewall and servo/battery tray...won't take long....but I did something different this time...instead of cutting formers and bending/gluing the slabs onto them, I cut longitudinal sections that are keyed on both ends...then I'll make templates for the taper of both the fore and aft sections of the fuselage, and cut the tapers with a hot wire.

Plans are for a Cobra 2820/14 840 kV motor, 60 Amp ESC 2600mah 60C 4S

Fuselage is 1/2" rigid insulation....Wings and feathers are 3/16" Elmers board

This build is in preparation for a 60" - 66" balsa version with retracts....just want to make sure it'll fly before I start cutting balsa

Assembling the fuselage....with help....lol
I cut the hot wire templates for the hatch and the fore and aft tapers.....

Got the fuse tapered, radiused, and sanded, but I'm concerned about the surface area of the stab and elevator...
and the size of the fin....gonna do a little ciphering on tail volumes...they might end up a bit bigger than scale...

I'm happy with the progress on the brown paper covering.it helps a lot to wet both the paper and the foam....Captain Fantail aggrees

The original stab is on the left, the new one is on the right....roughly 10% bigger with the elevator extended to the ends..the fin was OK,
but I added the reverse curve...I got the tail volumes almost the same as a Ryan Navion.....Vv = 0....Continue Reading
Posted by Old_Pilot | Nov 21, 2020 @ 04:15 PM | 4,456 Views
24 in Einzpfeil Maiden (1 min 52 sec)

She's featured in this month's AMA magazine.......which is totally fricking amazing.......
Posted by Old_Pilot | Nov 19, 2020 @ 10:42 AM | 6,479 Views
Just finished this one....24" Einzpfeil with a PowerFun 64mm 11 blade fan 3500kv motor on 4S....Nacelle is a 16oz Chinet coffee cup...Holy St. Dilbert.....static thrust is unbelievable..3.2 lbs measured. I've got some 70mm fans that don't produce that much thrust...this thing is gonna be a bullet..... AUW is 30 oz.1.7:1.0 Thrust to Weight
Posted by Old_Pilot | Nov 03, 2020 @ 06:44 AM | 7,058 Views
Had a request for info on what I use for the leading edge on my foamies

I use faux Carbon Fiber tape, cut into 2" wide strips...available at most auto parts store (O'Reilly's, AutoZone, Advance)
Posted by Old_Pilot | Oct 30, 2020 @ 06:17 AM | 7,823 Views
Just starting the drawings for this one......several of my buddies have been after me to build something more "scale". We'll see

Manufacturer claims this little fan will produce 1460 gr (3.2 lbs) of thrust......
Posted by Old_Pilot | Oct 25, 2020 @ 02:15 PM | 4,656 Views
In homage to Rusty-Gunn, I modified his original design (the Jimi Jetstream) to accept a 70mm EDF !

This is my way of saying thank you for so many wonderful designs over the years..Best wishes to Rusty

Note, the Jimi Jetstream was the first foamie I ever built....started me down the flat jet road......

30" WS 50% KFM-2 wing
70mm Powerfun 12 blade fan
3400 kv motor
80 Amp ESC
3300 mah 50C 4 cell
19 gram MG servos
Lemon 6 channel receiver with satellite
The nacelle is a 22 oz plastic stadium cup
Airframe is 3/16" Elmers board

Weather will have to get better before I maiden her
Posted by Old_Pilot | Oct 25, 2020 @ 08:15 AM | 2,967 Views
Already thinking about the next build....built this one back in 2014 with twin 64 mm fans....I'm thinking twin 70's this time
Posted by Old_Pilot | Oct 23, 2020 @ 06:00 PM | 5,620 Views
I had a mischief of a time unfolding the canopy for the Jetstream......I finally modeled the thing using 3D faces and unfolded each face using point-to-point projection.....I test cut the canopy out of heavy card stock, just to make sure
Posted by Old_Pilot | Oct 18, 2020 @ 09:45 AM | 4,871 Views
Messing around with an old design....30" Jetstream with a 70mm fan...based on the Jimi and Judi Jetstream....the originals were prop-in-slot, and excellent flyers designed by Rusty-Gunn (RC Groups).....unfolding the canopy for the fan mount was a witch.......

As a side note, the Jetstream was the first foamie I ever built....many thanks
Posted by Old_Pilot | Oct 15, 2020 @ 09:56 AM | 3,063 Views
The attached video was sent to me by a middle school teacher in Cologne, Germany.......he converted my Einzpfeil flat jet into a catapult launched glider as part of one of his workshop projects with the kids....what better way to be introduced to the dynamics of flight than to experiment with an easy to build glider...

Probably the nicest compliment I've ever received with regards to one of my airframes

Now to go deflate my head.....LOL

Einzpfeil catapult glider (1 min 21 sec)

Posted by Old_Pilot | Oct 11, 2020 @ 09:13 AM | 2,791 Views
Just finished this one.......with the new fan and nacelle.....will maiden when the weather clears

27" WS, 12 blade 70 mm fan, 22oz stadium cup nacelle (fits perfectly) 19 gr servos, 80 amp ESC, 3300mah 60C 4S battery, Lemon 6 channel receiver

33 ounces all up weight....64ounces of measured thrust
Posted by Old_Pilot | Sep 12, 2020 @ 11:43 AM | 2,462 Views
It was SPECTACULAR !....She was flying just fine, so I decided to open the throttles......and then....the fans quit, lots of smoke trails, and in she went...First thoughts are that two high amp draw fans and one high C (60C) battery are OK...until you try to push that much amperage through one Deans plug....pretty sure that's where the fire started..looks like I let the smoke out of everything....total loss...but it was worth watching the crash !..........LOL
Posted by Old_Pilot | Sep 03, 2020 @ 06:54 AM | 5,796 Views
This one looked like it had promise....until I checked the nacelles......not gonna waste material

Well SNUFF !......I've hit a snag,,a big snag....In its current configuration, there's not enough area at the nacelle inlets to satisfy the fan sweep area.....one thing I've learned about these fans.....I need to provide 100-125% inlet area, so the fan doesn't waste any energy just trying to get air to the rotor blades..in this case, I'm only providing about 70% of inlet area....long story short, the fans will starve at the inlet....

If you limit the amount of air going in, you reduce the amount of air going out......now you see why all my jets have nacelles that are external of the fuselage...e.g. the S-3, the SU-25, the A-9, and the modified CF-105
Posted by Old_Pilot | Aug 27, 2020 @ 01:11 PM | 7,747 Views
Northrop YA-9A....Flight ready

48" WS. (2) 12 blade 70mm fans, 3400 kv motors, 80 Amp ESC's,
5000 mah 60C 4 cell battery, 63 ounces all up, almost 8 lbs of thrust (measured),
50% KFM-2 wing.

"Laura" will prevent a maiden anytime soon....will post video if successful

Flight Surfaces are 3/16" Elmers Board
Fuselage is cut from 1/2" pink rigid insulation
Nacelles are cut from 2" pink rigid insulation
Posted by Old_Pilot | Aug 07, 2020 @ 06:16 AM | 6,657 Views
Finally got this one sorted electronically..gonna try to maiden her this morning......video if successful
Posted by Old_Pilot | Jul 26, 2020 @ 02:31 PM | 7,956 Views
Progress has been slow, but I'm getting closer...still fiddling with how to secure the wing, given the thrust to weight ratio....but I'm getting to the short rows...control horns and push rods..

She'll fly pretty soon....all up weight will be right at 3 1/2 lbs, but the new fans will generate almost 8 lbs of measured thrust....she ought to be a bullet
Posted by Old_Pilot | Jul 22, 2020 @ 05:40 AM | 5,512 Views
I've had to change the fan for my 70 mm flat jets to this one.


it's a little bigger than the ones I'd been buying and no longer fits the original coffee cup nacelle...so I needed to find a new nacelle cup....this is a 22 oz plastic drink cup that fit's perfectly ! They are referred to as "Stadium Cups"
Posted by Old_Pilot | Jun 14, 2020 @ 07:29 PM | 4,958 Views
Apparently there wasn't a nickname for the YA-9.....I'm calling it the "Grunt"

Got a bit more done.....still a ways to go though
Posted by Old_Pilot | Jun 08, 2020 @ 10:57 AM | 4,673 Views
Greetings all,

Most of my larger fuselages are cut from "1/2 nominal" pink Formular.....Unfortunately that "1/2" ranges from between 0.55 to 0.60 inches...so I decided to make a hotwire slab cutter for true 1/2" (12.2 mm) foam....

A piece of ply, some 1/2" square dowels, a couple of machine screws, some washers, knurled knobs, and a couple of stout die springs
Posted by Old_Pilot | Jun 06, 2020 @ 07:18 AM | 5,924 Views
Maiden didn't end well...she took off in trim, and I was flying her around at about half throttle, making sure of input response....no bad habits, good roll rate....then I decided to open the throttles all the way, and WHAM, the port ESC/EDF shut down...and she cartwheeled into the runway...broke her all to pieces. I knew I was at the upper limit of the ESC's (65 amp)....Obviously, I was too close....If I'd been 3 mistakes high, I probably could have saved her. As it was I about 10 feet off the ground at close to 80 mph.....Pretty good size debris field....it was spectacular !

Oh well, I'll build her again