jimkron

I just Erstflugged today.
http://www.youtube.com/watch?v=z_5TmC94BF0

fockewulf37

My Feedback: (102)

Congratulations on the Maiden.... Ok Now comes the Questions... What was your CG? Did you use try or use any flap?

I bet you can get 8-10 minute flights with the excess power that you have with the 2 160's...

Ty

jimkron

The CG was right at 151mm from the "crook" in wing. Still, during the flight we thought the plane was a little nose heavy and we talked about moving the CG back an eighth. The plane nosedived a tad when inverted. More testing needed. I think I had a pound of nose weight.

Full flaps on landing. No flaps on takeoff. The plane flew twice and both landings were too slow. Need to hold power with a plane that heavy 35 lbs (must have been that cockpit kit )

At high altitude we flew real slow with no bad habits.

All four lipos were cool on landing. I was very nervous on that one but added some holes in the firewall that helped with airflow. The flights were only 5 minutes or so. Fully charged the batts were 4.2 volts per cell and each was 3.9 on landing. I probably had more flight time but did not want to push it. So much depends on flying style.

The engines were great. Amazing power with 20-10 props. The plane makes does make a "whapping" noise that I attribute to the rear pusher prop. I've noticed that in other rear engine videos.

I was going to do another short build video to show a few mods people might be interested in. My mod of the Sierra Landing Gear is a must.

Jim

glazier808

My Feedback: (1)

Great job on the maiden!

Can't blame ya for "relaxing" there at the end!

I was puckered just watching!!!

I thought I saw a crosswind pick up in the middle of it all?

Perhaps slightly nose heavy?(good for a maiden tho)
Casey

jimkron

The crosswind was bad enough that we almost canceled the maiden. It was swirling so much that we kept changing takeoff direction.[X(]
Agree on the "nose heavy" for maiden.
The low flybys were full throttle with no real tailwind. The one scale flyby in the video was probably 65% throttle. Not bad for a 35 lb electric.

jim

pandissix

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Well done!!! Nice to finally see some one deliver on a build and fly it. Well played

bcrc

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Great flight !! Congratulations !

Did you have 5S2P on each motor? What was the cell capacity ? Have you checked yet how much you used in the 5 minute flights ?

jimkron

Thanks all. I'm at work now but will check on how much capacity is left.
Each motor has 2 Hyperion 5s lipos, 5000ma, 25c.

TA152

Wow! Looking good But, how could it be so heavy? Would like to know if it can be flown at slower speeds too, and do the pilot test it with full flaps?

jimkron

I was guessing more like 31lbs originally. I'm hoping the scale is off.
The extra weight is in the landing gear, cockpit, full pilot, 4 lipos, 2 esc, motor and lipo cable extensions, carbon fiber reinforcement of landing gear box and front fuselage, and maybe a pound of nose weight. I'd love to see the weight of a gas or nitro version. Remember, I moved a lot of heavy stuff forward like lipos. Heavy metal engines, mufflers, gas tanks, etc might be lighter overall but you might need a lot of extra nose weight to get it balanced. Just hold any heavy engine in your hand and imagine that on the tail of a plane with a big prop. The original German plane had the rear engine no where near the tail. Balance is a challenge no matter what your source of power with a Do335.

We flew the plane slowly for several minutes of the first flight. No bad stall characteristics. We used about 1 inch of flaps on landing. The plane will fall out of the sky with full flaps as seen in the video. You need to hold some power through the landing and be ready to add power if you get too slow. At 35 lbs it's not chop and glide.

bcrc

My Feedback: (19)

Did you figure out how long you could fly a typical flight (i.e., flying most of the time at a "comfortable" power level) with the 2 5000 packs ??

bcrc

My Feedback: (19)

Have you done any more experimenting with the CG location ?

jimkron

I only checked one pair of 5s for the front motor at 5000mah each. One pack put back 1313mah. The other put back 1564mah. This was with fairly agressive flying.
We need more experimenting this weekend but I'm guessing the next flights will be in the 7-8 minutes. Then we'll check again.

The CG seemed fine for starters at 151mm at the crook. The plane was nose heavy though when inverted. I'll probably move the CG back a 1/4 inch or so and rebalance. In general, I tried to balance the plane with the prop shaft parallel to the ground. I figured this would keep the tail up a little longer on landing. Still, I think it would look better flying with a very slight nose up. WHATEVER YOU DO, DON'T HIT THE BOTTOM DORSEL FIN ON LANDING![] Very bad idea.

Jim

TA152

Hope to make a Erstflug in a couple of weeks[sm=teeth_smile.gif] Have worked a lot with the cooling of the aft engine and have moved the retracts 12mm out in the wing to make space for 5,5" wheels

Mr DJ

TA

What engines (gas/glow) or motors (electric) are you using?

Mr DJ

Mr DJ

The DO 335 Master himself: Jim, standing next to the Man: Mr DJ at Warbirds over Delaware (WOD) passed Saturday. Jim flew out from Cali, I drove up from MD.Too bad Jim didn't have his 335 there, she would have been a show stopper. The second photo of our backs show us looking at my X-13' Cessna 182 that I sold to a fine Gent.

Next year (in my dreams), I plan to have my 335, DC-3, and two special turbines at WOD.

Mr DJ

TA152

Hi DJ .

Take a look at post #262

Mr DJ

TA,

Now I remember

Mr DJ

bcrc

My Feedback: (19)

Please give me details on your mod of the Sierra gear. Lots of photos please !!
Thank you.

bcrc

My Feedback: (19)

Please let us know about your mod to the Sierra landing gear. Also, please let us know about the other mods we might be interested in.
Thank you,
Brian

jimkron

Here are some pics of my mod for the lipo hatch and strut.
The four lipos (20s total) sit standing up in front of the canopy.
Then, I needed to lengthen the trailing link so the strut would fit in the wheel well. I bought the coupling at Home Depot and cut it down to fit in trailing link. The hex shaped coupling made it easier to attach. I used epoxy putty to attach it higher on the strut. The epoxy is a dark gray when dry so I painted it with some silver. You would never know.
I also bought the very nice Sierra brakes and hooked them into the down elevator on my transmitter. Works great.
The final pictures are my inner stuffings.

jim

bcrc

My Feedback: (19)

TA152:
Have you flown your DO-335 with the Laser engines ? If so, how did it go. How did you like the engines?
Thanks,
Brian

TA152

Hi Brian.

Haven't flown yet. Have been really busy this summer, but have changed the front engine to a 160V. I needed weight and think the extra power will be more safe.
Working with the exhaust now and hope to test the engines this weekend
Have used Laser in several years, and I'm very pleased with the design and power. Have one Laser100, three 120,one 160V, two 200V and one 360V [8D]

Ram-bro

My Feedback: (101)

exhaust on an electric?......

TA152

Electric?