ElectraJet Flight Log

*****Flight Updates 06/28/03*****

Well after having 4 or 5 days with strong gust. I woke this morning and looked out and the trees were still YES!

I thought all right it’s time to take the ElectraJet out for its maiden flight finally! Well I loaded it up in the car along with two charged batteries and a freshly charged transmitter and headed to my RC clubs field.

Well I arrived there about 10 o’clock and WHAT, there is like 50 cars there and it’s a weekday! Go figure all this waiting and I forgot, we are having an Old Timers event and the club is closed to regular flying.

Doesn’t that just beat all, wait and wait then the weather gets good and the field is running an event. Well on my trip home, I started thinking, hey this is a Park flyer lets just do that! We have a local soccer field by the house that is really open no trees, so I head over there.

Excellent it’s clear! Not a person there, perfect for me to finally see how this ElectraJet flies.

After some preflight checks, all looks good, so I hook the radio up to my neck strap take the plane to the middle of the field, put full throttle on and give the plane a good fling.The ElectraJet is off and climbing!!!! And all over the place!!! I am playing heck to keep it airborne, it wants to stall and roll over on me. Well I soon realize that my initial trim is way too much up. You can bet this was hand full, a plane that is rolling and trying to stall and I am at almost full down to keep it from nosing up and stalling!!!!!!

Well finally after I keep giving it down trim till I run out of trim it levels out. Fortunately that was just about perfect, maybe a little more down trim would be nice but I do have control of the plane now! WOW my knees are knocking...

Anyway now that I have her some what trimmed out, I began to just fly some figure eights and see how the plane turns.Well the plane turns really nice as long as you have some good forward speed but if you hit the turn too hard and slow it tends to roll over and stall and the elevator is really sensitive.

The wind is in the 7-10 MPH range out in this field, seems to have picked up a little by the time I got there, so up wind it was pretty docile, but downwind it was clipping along pretty good but it handles the wind a lot better than I thought such a light plane would.

Well after about 6 minutes I bring her down to nice smooth landing, WOW what a first flight!!!!

Well after some inspection to why such a extreme miscalculation on the trim I look at the aileron from the bottom and realize that the way I had them set was centered and not flat or horizontal with the bottom of the wing. (Something to go in the tips section for sure!)...

Anyway I change the batteries out and since I didn’t bring any tools with me to the soccer field I just go again with the trim full down. Well the second flight was not near as much a knee knocker as the first. I did get to do some low fly bys and this plane also barrel rolls excellent. I am also very impressed with the vertical flight and was able to get half a Cuban 8 out of it (they have a name for this maneuver but I can’t remember right now). I did use the down wind speed, but I think on a really calm day and a fully trimmed out plane I will be able to get a full Cuban 8 out of it.

I tried inverted one time, but it still needs some more trimming out before we try that again whew. Well this flight didn’t last quite as long as the first, could have been not a fully charged battery or maybe just that my throttle management was max on this whole fight

Well Now comes the third flight of the ElectraJet.

I still felt like maybe there was something else that makes it want to push up so much and I remembered that when I first mounted the motor, I mounted it with the gear case down and that does make a difference of about an inch to where the center of the prop is. Anyway I knew the photo showed it up instead down and deicide to take the motor cover off and flip the engine around so the prop would set higher above the wing as it does with the gear case up...

BIG MISTAKE!!!!! I figured it that might affect the trim a little and fix that slight tendency to nose up and still wanting to climb at neutral, but I had no Idea how much!!

Anyway I gave it good toss as I did on the first two flights and right off I knew I now had way to much down trim and I mean way too much! So much that full up gave level flight!!!! Talk about another wild ride!! Back to stalling and rolling all over the place. I once again was very busy just trying to keep some type of level flight while I tried to trim it out.

Well some how, guess all the stick time I have gained over the years had my fingers working before I could think about it and I did finally somehow got it trimmed out to where it I could control it... This time the trim was pretty much maxed out for up talk about a slight change huh!! Well after all that fun of just trying to control the plane the battery was slowing so I decided it’s time to land, I need a rest from this flight!!!

One thing to note another nice smooth landing. That is the one thing that I can say for sure about these. They really do land nice; I floated the second one right close to my feet so close I didn't have to make three steps to pick it up! I also learned that prop gear box position makes a big difference and I will be changing the engine back to the gear case down as it flew more stable and faster in this position to me.

Needless to say after this third flight I decided it was time to pack it up and work some kinks out back at the shop. I would have to say out of my three flights the second was the best, but none of them were really optimum with a truly trimmed out plane to give a fair review of the ElectraJet flight. I have learned quite of few things that should make my next trip to the field a little more confident.

Elevator on these is really touchy, so I will set some ATV and reduce the travel since I have a computer radio this will be real easy solve. On a conventional radio I would say, set the arms to have the least travel, only problem with this is you will lose some aileron travel and I love that part, the rolls were tight and even with lots of aileron travel the turns didn’t seem too touchy like the elevator did.

Anyway that’s about all for now.

I think I need a strong drink and I don’t drink!!!!

Any Suggestions on improving flight performance would be appreciated. I also wonder if maybe it is a little tail heavy, because on a conventional gas planes I have flown when they want to roll like this one did, it usually indicates that they are tail heavy... Any thoughts?
 

*****UPDATES*****      6/25/03

Well I did another test run today since the wind is blowing like crazy again, go figure wait over ten days for the batteries and just about every day was calm..... Now that I have the batteries guess what the wind decides to do....$#%%#$%#

This test run I used a Tach and checked the RPM at in 1 minute incrementals.

Here is the data I came up with... Yes I know I do tend to get a little over board on the scientific data guess that just the engineer in me coming out!!!

Minute    RPM     Throttle at Full 

1             5250

2             5300

3             5300

4             5250

5             4800

6             4200

7             4100

8             3600

9             1200

10           1200

11           1200  Prop stop turning but still have full control of servos.

Batteries didn't get near as hot this time not sure why the difference... If I could find my thermal probe for my DVM I would have taken temp reading as well...

I did charge the batteries at a different rate on the second test, wonder if that was the difference.

Still waiting in the weather give me some calm winds!

*****UPDATES*****     6/24/03

YES! My batteries came in today finally !!! AND GUESS WHAT, THE WIND BLEW 20 MPH GUST ALL DAY @#@#@.. Well I figured I could at least give them a field test tonight.

Well first thing was to install the pack in the plane. GUESS WHAT THE CG was perfect if anything a hair nose heavy, but really closer to a perfect balance. It was perfect with the canopy off, but with it on it almost makes it tip forward slightly at same CG location. Couldn't be better that is CG I would have setup even if I had to move something.

So next I used a MRC959 charger and charged a pack up. Well after a good charge it peaked at 11.38 volts and was pretty warm. I hooked up the battery to the planes speed controller, then put it in between the arms of a office chair so it couldn't fly off and the prop was clear and started her up.

WOW the thrust was pretty impressive, it actually got the chair to turn some in place.

Here is what the initial charge of a 9.6 volt  8 cell 2/3 1000mah pack discharged at.

4.45 seconds full tilt  power even with aileron and elevator movement.

2.35 seconds of semi good power definitely enough to still fly around and with.

30 seconds of greatly reduced thrust might be enough to fly on but I would be looking at my approach for landing..

Well I am impressed need less to say. I figure with any throttle management at all this plane with these cells is good for 6 minute flights no problem and maybe upwards of 7 to 8 minutes of flight.

WOW WOW HOT BATTERIES AND I MEAN HOT... TO HOT TO HOLD... I AM PLAYING HOT POTATO WITH THE PACK.

Wonder if this is normal? I raced RC cars before and I know the batteries get rather warm in them as well. But I think this was even warmer! Wonder if this is a characteristic of NiMh's?  I am new to NiMh's but wow this pack was hot! I have since let it cool and charged it again, seems to be just fine so who knows!

I am excited this looks to be fun plane. Now if the weather will just cooperate and give some calm weather I will head to the RC field for it's maiden flight and my fight review of the ElectraJet..

I have chosen my batteries and have them on order now, can't wait to see the UPS man !!!

I chose the 8 2/3A nimh cells with a capacity 1000mah. It was a weight to capacity toss up, but I think the with less then 2oz's of difference the 1000mah will give me longer flight times, as there really is quite of bit of wing surface on the ElectraJet. With these batteries the plane will weigh in a at 20.3oz.  I used a wing loading calculator and the wing loading with this setup will be about 8oz a square foot. Which puts it in the glider arena for sure.

Right now I am still looking at batteries for it... I am leaning towards these two.

* 8 AAA nimh cells with a capacity 800mah, the weight on these is 4.5oz at 9.6V..

* 8 2/3 nimh cells with a capacity 1000mah, the weight on these is 6.3oz at 9.6V..

Which of these do you think will perform best?

And for reference the weight of plane came in a 14oz even. The specs say 16-24oz so I am really in the ballpark on this one. If I keep it under 6oz for the battery I will be right in the middle of the factory spec's, so my quest is to find the most battery bang for the weight.

I figure in all even with painting of the canopy and the modifications, this plane took me less then 7 hours to complete...

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