Pulse XT25e #4 Flight Ready!

I finished the replacement Pulse this afternoon, completing the motor and electrical system installation, the receiver, installed the canopy, and the wing. I programmed the transmitter and voila, done!

Earlier I power tested the HeadsUpRC Power 32 (rated for 800 watts) with the HobbyWing FunFly 60A ESC using a 4S 3300 mAh battery and an APC 12x8e. The peak wattage was 820, running nominally on full throttle at 740 watts. She drew around 45A Sweet spot. I had tried a 12x6 Xoar, and it RN fine, pretty close to the same numbers, but a bit less power and thrust. I left her with the 12x8.

 

On inspecting the motor, I found that one of the power couplings was not connected. I wonder if this contributed to the crash... I had applied power and got at best a mushy response. I decided to resolder all three. I also lubed the bearing.

 

Resoldered and shrink wrapped.

 

Motor in place. I decided to put in one thin washer to give a smidge of right offset.

 

 

 

 

Welcome to Pulse XT25e Number 4!

Looking forward to maiden flight sometime this week, when the weather settles in!

 

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PulseXT 25e #4 Arrived Today!

 

The latest replacement PulseXT arrived today via FedEx! I love Horizon Hobby! I've half built it already, this being my fourth frickin' one...

 

Stopped for the night. Looks like SkunkWorks, and it's actually hiding my plane, even down to the Dixie cups covering the wheel pants, from my frickin' cat, who like to chew the corners of my planes. Well one does (we think it's Neko... I have three Siberians, two who love us and one who clearly tolerates us). Tomorrow, wings and servos, canopy, and power system is all that's left! Weather will be sucky the next several days so. I am unlucky to get to maiden it for several days.

 

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A Good Day!

Nice weather conditions lead to gentle morning winds. overcast, mostly cloudy with spotty sunshine breaking through. Got three flights in on the Sbach, all fun and lacking in troubling excitement. I flew very basically, a few simple stall turns, Cubans and inverted. she flies sweet in all orientations. Concious of my poor orientation feelings last time I was extra attentive today. One hard landing as I get used to her floating in ground effect. I really want to get awa from spoilers. She doesn't peel off speed well, though you can hear wind whistling through the free turning 17" prop as she comes in off power over the threshold.

Decent flight times. Got easy 6 min from both the 4000 and 3300 mAh batteries, not seeing a reason to go bigger and wonder if just flying 3300's is the way to go? Lighter battery, adequate flight time.

Met Kelly who came over with his son from the soccer fields. They had seen the Sbach and had some free time so dropped by and got a nice welcome from me and John, who himself is a frequent visitor from Florida. John was flying his Revolver (why didn't I think to get a pic?). I had Aidan's 450, but he hasn't flown it yet and I wasn't going to fly it without him. He slept in today.

A couple of days ago I filed for Aidan's AMA license, and now he can fly without anyone getting their tighties in a wad. He's been flying under my filed student endorsement as I am an Intro pilot, but this way none of the crannies will give us any grief. I really wanted to see his 450 fly and get him on the sticks!

On the way home I stopped by the Orange Grove Hobby Shop and picked up some 2-1/4" tires from Jason for Aidan's 450. The bigger tires make for better ground handling in the grass than the stock ones, which I think are a bit more than an inch.

My replacement Pulse arrives today! Will surely get started on putting her together, shouldn't take long at all.

Time to break out the helis! Looking to fly again tomorrow!

 

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That's a Bummer...

So... According to specs the flight weight of my Sbach 70 tops at 5.5 lbs. With a 6S 4000 mAh 40C battery it weighs in at 7 lbs. I don't know what universe it would weigh in at 5.5 lbs.

And... I ran another time run on that battery and I got 5.5 min at 3/4 throttle down to 3.5V per cell. That's pathetic. I think I got 6-7 minutes with the 2650 mAh 25C ones. I don't think I can fit a 5000 mAh battery in there, let alone the extra weight.

Bummer.

UPDATE: I made up a mockup of the smallest 6S 5000 mAh battery I could find, the Turnigy from HobbyKing, 150x49x52. It won't fit through the frame to be properly positioned to maintain CG. It can enter the fuse from the next frame back, but on moving it forward it runs into the wing tube.

 

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Lucky Stupid: Series vs Parallel

I have been making a fundamental mistake in my use of series to increase voltage and capacity: it doesn't do both.

I thought putting them in series increased the voltage AND the capacity was added. It's not...

Series: increase voltage, no increase in capacity. 2 x 3S 2650 mAh gives 6S 2650 mAh.

Parallel: Increases capacity, but does not increase voltage. 2 x 3S 2650 gives 3S 5300 mAh

 

 

 

http://www.zbattery.com/Connecting-Batteries-in-Series-or-Parallel

I have been putting batteries in series knowing I was increasing the voltage andthinking I was ALSO increasing capacity. When I flew the Sbach the other day with two 3S 3300 mAh batteries in series I got 6S but only 3300 mAh! That bought me 6 min total battery to exhaustion time (3.7V per cell). Dammit... I was trying to get more 6S mAh for longer flight times. Guess I will need to by a couple higher mAh 6S batteries.

I have have been mistaken for years... lucky stupid.

Thanks to Kenny Chandler for doubting me!

 

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Aidan Builds His Eflite Alpha Sport 450

Aidan has gone out with me a couple of times to the RC airfield, and today he finally committed to wanting to do this regularly! We bought him his own Eflite Alpha Sport 450, the perfect trainer, the one I started with several years ago.

He did a wonderful job with it! We set it up and programmed it into my Spektrum DX8, setting his DX7s up as a slave trainer. Tomorrow we hope to get to fly it!

 

 

 

 

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Skyline/Goldwing Sbach 70 Maiden!

Well, after the debacles that ended the life of my third beloved Eflite Pulse XT25e, I had decided NOT to maiden my brand new baby Sbach.  Aidan and I sat around watching others fly while Kenny Chandler cajoled me into manning up, not letting one mistake keep me from flying the Sbach (he rewrote history as I made a bunch of mistakes today). I wanted to fly sooooo bad. I also knew that this would be a basic flight behaviors and trim flight, but maiden's need your skills to be focused and sharp as they are often unpredictable and perilous. I also knew if I walked away a broken man today, it would incredibly stressful coming back to maiden: get back on the horse, son, its just an airplane.

Being of unsound mind, I listened to the white devil, and we flew her together, me pilot, Kenny wing nut, Aidan cameraman.

Pre-maiden photo op

First flight battery pack. Two 3S 2650 mAh Turnigy Nanotech's should give me at least 4 minutes.

Kenny and me preflighting.

Taxi tests.  Out...

and back.

Preflight conference with Kenny Chandler, best bud, evil man.

The flight went sweet. Nice rollout but she leapt into the air when she was ready. Low rates but with more elevator than I would need. I will decrease elevator throw and increase expo on both low and mid rates. I flew the entire flight on low rates. I noticed on landing that I had too much elevator authority. She flew perfectly balanced, the CG was spot on. I had forgotten to weigh her, but with full throttle she had unlimited vertical and good speed. She is big, so seems to move a bit slower when in fact she was hauling ass.

Aidan did a nice job with the video, the autofocus was off a lot, but he kept it in frame nicely!  Thanks Aidan for thinking to video the maiden!

Last Flights of the Pulse #3

After two great days of flying I felt I had my flying fingers back. Today something was off... I kept telling Aidan (my eldest son, new pilot) that I was screwing up my right/left orientation in odd flight orientations, and a couple of times I had to make quick saves. I flew the first battery otherwise fine, but on the final landing approach, I deployed the spoilers and underestimated the loss of airspeed and lift. Despite adding power she was mushy and landed short and hard, ripping off the landing gear, tossing the fixed canopy (its glued on, it doesn't come off), and poking holes in the wing and bottom of the fuse. I've done this before, easy fixes in the pits. The second flight was similar, making stupid orientation mistakes, then on landing I made the same mistake in a less forgiving place, the perfect storm.

The spoilers were certainly reducing lift, but they were also increasing drag and making control movements sluggish. I had mastered them last time I flew, but today was flying behind the aircraft. As my Marine pilots would say, "We're on takeoff roll and he's still in the parking lot getting out of the car...".  I came in over the trees on the south end, always gnarlier on approach, and she started to waffle. Power... she stalled rolling right, I tried to correct, but rolled her more right with dumb thumbs and she rolled quickly right into the last tree before the field and fell into the woods with a whack...

First run up before first take-off.

Out to the center... and off!

Landed short on the other side of the road...

Scene of the resting spot after the slide following the crash. It was actually pretty cool...

Surprisingly not destroyed. The wheel pant punched a hole in the wing as the landing gear were ripped off the plane, the wheel pants off the landing gear. 

On the bench, discovered a few other problems. Had to repair a wing rib under the hole the wheel pant drilled. Used super cement to put the landing gear back on (its probably why the wheels didn't fall off in the second crash, but the fuse ripped in half). Aidan put the wheel pants back on.  Used "field cote" (packing tape) to repair the holes. 

Everything back to normal! Electronics all good.

Field repairs look good.

And we are off for the second, final flight. Flew fine, whipped it around a bit. Wind shifted to require a southern approach over the woods. I didn't make it.

Aidan in the woods immediately off the south end (The Woods of Mordor). Nature all over him. The plane wasn't more than 10 feet in, but it was thick. He was a good egg going in for my plane, my being in shorts and flip-flops...

The carnage did not look so bad at first...

Aidan said, "This man did this...".

Yes... yes I did.

Aidan conducting the autopsy. He removed all the hardware, all of it was fine. Battery was not "crashed".

It became obvious that the cote was holding the forward fuse together. This is really not repairable.

Wing is twisted. I have always considered the wing the heart of the airplane, and breaking it up to put it in the trash was heartrending.

Her ignominious end, the bottom of a MCRCC trashcan, stripped of her hardware... sniff.

I have received funding authority to purchase a new Pulse 25XT airframe! Ordered and shipping tomorrow! This, I am embarrassed to admit, will be number 4, in 7 years.

Not being a fool, I decided not to maiden the Sbach. It not being Kenny's airplane, he cajoled me into flying it anyway... Next post!