Carl Goldberg Electra

[BrianW]

So with the inclement weather we've had the last couple of weekends I've finally managed to finish the plane. Final weight wound up being at about 38 oz, which is a bit heavier than some, but lighter than the original weight with the can motor and NiCads. The plane balances right on the middle of the CG range with the battery against the bulkhead.

Completed Electra

I wound up needing to put in one of the switching BECs I showed in the other thread. With that, there are no further brownout issues and it seems to be quite solid.

Now if I could only get some reasonable weather to maiden it...

[JohnOSullivan]

I'm surprised that the weight was as high as 38 oz.
The typical weight of a Gentle Lady was about 22-25 ozs as a glider. the Electra was a similar design and with old Nicad and brushed motor "Arc Welder" stuff (quote from Astroflyer). should have come out under 40 ozs. I would have expected that with modern electrics It should have come out under 32 ozs.
However at 38 ozs, It should still be a great performer.
Good flying!

[BrianW]

Interesting... I was going by the ARF ready-to-fly weight on the Goldberg website, which is listed at 48 oz. I could easily drop off 3 oz or so by going from the 2200 battery I have in there down to a 1300, but it would mean probably adding another 1/4-1/2 oz of nose weight to still balance. I made no efforts to save weight right up in the nose, hence the alloy spinner, doubled firewall, and threaded brass pillars instead of nuts. All that effectively is my noseweight, so it would have been possible to go lighter. It would have required extending the nose (as you suggested earlier, John) but after looking at how that would complicate the cowl/canopy/wing mounting, I decided I'd rather just be a bit heavy and keep it simple.

A few guys on RC groups have built them in the 32-35 oz range, although that was definitely with smaller batteries (I think a 850 at the lower end of the weight range). There were a few steps in the build process where I know I added weight, but it was usually because I wouldn't trust the airframe without it. Well, except for a few glue spills...

I'm looking forward to flying it!

[retiredVTT]

Congrats Brian, she's a thing of beauty....great color combo..!

I think this week Sunday is supposed to be the optimum day...if I think of it I'll bring the vid camera..!

Later Edit...well, maybe Sunday afternoon..now their calling for rain in the AM...@%$&$!

Bill

[AndrewS]

Looking forward to seeing her in the air Brian.
Fingers crossed for Sunday

Andrew

[JohnOSullivan]

Don't be worried about the weight. It will fly well at 40-48 ozs, but sink rate would be better at lower wing loading.
The 2200 batteries are fine and without lengthening the nose, they will give you an easier time in getting a suitable CG position.

Just for comparison, I use 1200mah in my 1.8m Pulsar (all up weight 21 ozs), 1800mah in my 2.3m Hyper (27 ozs) and 2250mah in my 3.2m Pulsar (49 ozs) and Magellan 2.5m (54 ozs)
Whichever way you go it will be a far more efficient model than when it was originally designed for 6 cell Nicads and Brushed motors.

With Trevors new (and well built) T tail model . (I believe Tim Osborn built it and a fine job he did on it). Trevor would like to convert it to Electric, but I advised flying it as a pure glider for the remainder of the season. With the the other sailplane fliers, we should concentrate on a day out at Lawrencetown.
The first time you launch over the edge is a bit of a "Pucker Factor", but when you see it rise rather than head for the waves, the thrill of slope soaring will sell you on it.
Hour long flights are commonplace on the slope. For weak lift conditions, the added security of a motor is a little bit of a rescue factor.

Sailplane flying is rather like the difference between sail boats and power boats.
It teaches you the intricate nuances of air currents and how best to use them to gain altitude.

[AndrewS]

John is right about the "pucker factor". The first time I had my Easy Glider Pro at the slope, it was harder than anything for me to throw the EGP over the edge, even thought I had just watched Rick fly it on a checkout flight. Still is a bit nerve racking but I know she flies just fine.

Andrew

[trevor]

sunday looks good for a trip

[BrianW]

It may eventually make it to the slope, but it definitely won't be tomorrow.

As far as flying it at Shannon Park tomorrow, I think I'm going to keep an eye on the wind. After putting this much work into it, I don't want to rush the maiden if the weather's not ideal.