Bird of Time ARF

[xviper]

Yes, a link to RCG would be handy. I hate RCG and the more work I have to do to find something, the less I go there.

[brk6188]

Sorry, but have no idea how to attach a link or attachment from RCG to this forum.

[davecee]

OK. what is the thread title?

[xviper]

Man, that was a pain to find it but here is his post ........................
https://www.rcgroups.com/forums/show...6&postcount=94

Flew mine today, three flights. Very disappointed. Had plenty of power to climb out at 45/50 degrees. Using Gens Ace 4 x 3800 pack as it is the only one that will fit and that comes close to balancing it. Flew very heavy and as though tail heavy, could not hold a good bank without it stalling out. Even shallow banking was unstable. Noted that there is no washout on my outboard wing panels -- not saying that there should be but --------.

Ben's spoiler/flap mechanism worked very well. I do need to tame down tailplane, need way less movement for full stick travel. This sensitivity could have contributed to my flight woes.

Back in the 70's flew the BoT pure glider and yes it was much lighter but it never felt out of control as my heavy electrified version does.

If only they had extended the nose forward of wing, quite a few ounces could have been saved off of flight ready weight and who needs a 3800 anyway, to get to thermal height.

All that's needed is to highlight the URL at the top of the screen, then "copy" and "paste" it here.
It was under "sailplane talk" instead of electric sailplanes where I think it should have been.

PS, I think this plane could really use a "Return to Home" device. When not being used for return home, the stabilizer helps theses sorts of gliders fly so much better. I had one in my EP converted BoT clone and it flew quite nicely, not as nice as the Mystique RES or Radian XL but still quite acceptable.

[Aros]

So was it simply a matter of being tail heavy? Obviously a EP version is going to weigh more than a non-powered but it sounds more like a CG thing the way I read it?

[xviper]

So was it simply a matter of being tail heavy? Obviously a EP version is going to weigh more than a non-powered but it sounds more like a CG thing the way I read it?

The EP version of this plane is simply a "regular" BoT with the nose cone cut off and ALL the lead weight removed. There is a huge donut of lead that's seems to be epoxied into the nose of the plane. I think when the manufacturer decided to market the EP, they simply didn't put the lead in. That amount of weight is much more than the weight of the motor and ESC up front. The weight made the non-EP balance fairly well. Take out the weight, add in the motor,ESC and a rather large battery (for a sailplane) and it is still tail heavy even though you have quite a bit of added weight. The big battery is quite a ways aft of where that lead used to be. Thus, the plane may already be heavier than the non-EP version but it's still tail heavy. There is just no space up front to add more weight inside. (You could stick weights to the outside of the nose but that looks quite ugly. Put enough weight to make it balance properly and it becomes really heavy.) One remedy that an owner devised was to add a section of fuselage before the wing so the motor, etc, had more leverage to balance the plane without adding weight up front. He made his BoT about 3 to 4 inches longer in the nose.

[fhhuber]

Electric BOT balanced pretty well when it used a brushed motor and NiCd battery.

The brushless motor is appx 60% of the weight of the brushed and the LiPo is less than 40% of the weight of the NiCd. And there's why its tail-heavy.

[doctormike]

The BOT that I electrified had steel ball bearings embedded in epoxy. A little difficult to remove. I use a 3700 3s in mine and it balances perfectly. I have nothing but good to say about my BOT. I have to use my spoilers to make the thing come down! I think it's mostly a matter of correct balance. Doc

[Aros]

The EP version of this plane is simply a "regular" BoT with the nose cone cut off and ALL the lead weight removed. There is a huge donut of lead that's seems to be epoxied into the nose of the plane. I think when the manufacturer decided to market the EP, they simply didn't put the lead in. That amount of weight is much more than the weight of the motor and ESC up front. The weight made the non-EP balance fairly well. Take out the weight, add in the motor,ESC and a rather large battery (for a sailplane) and it is still tail heavy even though you have quite a bit of added weight. The big battery is quite a ways aft of where that lead used to be. Thus, the plane may already be heavier than the non-EP version but it's still tail heavy. There is just no space up front to add more weight inside. (You could stick weights to the outside of the nose but that looks quite ugly. Put enough weight to make it balance properly and it becomes really heavy.) One remedy that an owner devised was to add a section of fuselage before the wing so the motor, etc, had more leverage to balance the plane without adding weight up front. He made his BoT about 3 to 4 inches longer in the nose.

Thanks for the detailed response. Wow that's a shame and will be a deal-breaker for me. Another shame. :(

[xviper]

Thanks for the detailed response. Wow that's a shame and will be a deal-breaker for me. Another shame. :(

It's a beautiful looking sailplane - very classic shape, good size (not too big, not too small). I think I'd still get one if Hobbico doesn't go bust. As fhhuber said, it's all in the balance and getting it right. The overall weight does make it come in fast and that's where some spoilers or airbrakes is a must. Of all the sailplanes I've owned, the BoT needs to be flown "gently" and with calculated movements. It won't turn on a dime without added power. Banking should be done in big arcs when under glide. For a sailplane, it's fast. When flying with Radians, it will still float past them at 50% more speed.

[fhhuber]

The electric just needing lead in the nose to make CG is a deal breaker?

That's all it takes. Lead to bring it up to the flying weight of the un-powered version, stuck as far forward as possible

With some practice you can learn to slow it down just before landing. Pull the nose up and ALMOST stall it. Get the tail back up before it becomes the first point of contact with the ground..

[Aros]

The electric just needing lead in the nose to make CG is a deal breaker?

After reading xviper's comments he said there's no more room in the nose to add more weight. I don't want to have to manipulate the nose (extend) or add unsightly external ballast. If those are my two choices to get it to fly balanced then yes, it would be a deal breaker for me.

[xviper]

One can get creative to add more weight to the nose but as is, it's very tight inside. I was even using a 4000mah, 4s battery and that wasn't enough. There is also some variation in weight distribution from on model to the next. Placement of servos and type of bellcrank used can change things. I think I attached some weights (very thin sheets of lead) to the outside that molded to the contours of the nose and hid it with tape. One can also get the extra heavy metal spinner/prop adapter and 3-blade prop from Esprit Model. Even tail heavy, the plane will fly with the proper technique or the aid of a stabilizer/flight controller.

[Aros]

Seems like they should have done a better job of engineering for the EP version instead of the shortcut of simply chopping off the nose for a power plant on a bird not designed for power. Those turkeys. :Confused:

[xviper]

I don't think Great Planes did anything in the way of engineering to produce the EP version. They did exactly what you said just to get a few more sales. In fact, I can save 50 bucks if I just buy the non-EP version and cut the nose off like I did my first one. With the future of Hobbico uncertain, there may be no EPs coming anymore.

[Aros]

Yeah I may do the same eventually. I don't want to be stuck looking for a NIB that is no longer available online if they go out of business.

[fhhuber]

There are weights made to go in the spinner affixed with the prop nut.

https://www.towerhobbies.com/cgi-bin/wti0001p?&I=LXK246

Or in the Electrifly WWI appx 35 inch span elecric ARF series I epoxied lead bird shot inside the cowls, lining the cowl with the needed weight.

There's room for weight...

[Aros]

Intrigued once again! :Cool:

[fhhuber]

Don't abandon an idea at the first problem..

There's also thin sheet lead. Certainly it would slide between the battery and fuselage sides.

[xviper]

Using a GliderDrive motor with its connections at the rear, it is possible to attach strips of weights around the motor without too much difficulty. This would the option I'll take with the next one.