New ride - tee hee

[Tim Wescott]

Paul Walker was giving away airplanes at the August meet in Auburn.  One of them was his Atlantis from 1988.  I took it.

Progress has been slow, but it has motor, tank & wheels and is ready to fly -- all I need now is fuel and courage.  If it doesn't rain tomorrow I'll be flying it -- if it does rain tomorrow it'll get a spinner cone and some of the hanger rash rubbed out & waxed.

I'm looking forward to a plane that's not only big and well built, but that's probably much better built than I could do.

[Chancey Chorney]

Wow.  Nice plane, and great deal too.

[Steve Helmick]

I think you'll want to point the muffler outlet downward. And what's with the APC prop? Out of TT's? And don't forget the lines and handle! You've not converted it to R/C, have you?   Steve

[Tim Wescott]

I think you'll want to point the muffler outlet downward. And what's with the APC prop? Out of TT's? And don't forget the lines and handle! You've not converted it to R/C, have you?   Steve

I'll be trying a number of props, that APC is just what was lying close to hand when I was fitting things up.  I'm thinking I may need a bit more grunt on a 64 ounce Atlantis than I need for a 53-ounce Twister, so I'm thinking I may need a smaller prop with the engine wound tighter.  But I'll be going through my prop collection.

I won't be converting it to RC, though -- apparently Paul hadn't quite figured out how to build planes yet when he did this one: one wing is an inch longer than the other, if you can imagine that!

[John Leidle]

   Probably ??  There's no mystery in the thought.

[Peter Grabenstein]

Tim, are sure C.G. is at the correct point  ?.
Unsure about your "heavy as a brick" stock muffler  .
Did Paul use the same engine/muffler Combo on this one ?.
Please don't use setup muffler outletpipe for a hair dryer    .
Peter  

[Mark Scarborough]

LA 46,, 12.25 x 3.75!!!!!!!!!!

does it have ground clearance,,the 46 will swing the prop with authority,, should be fine
some of my uh,, lighter planes (?) have done well with that combination
ok so they were not much lighter

[Tim Wescott]

Tim, are sure C.G. is at the correct point  ?.

If it's not exactly right it's in the neighborhood of right -- certainly close enough that the first flight shouldn't be hair-raising or artificially short.

Unsure about your "heavy as a brick" stock muffler  .
Did Paul use the same engine/muffler Combo on this one ?.

That's a not-too-heavy Tower muffler.  I need a muffler at my field, regardless.

Paul used a 40 FSR or something like that, but he strongly suggested I use a 46 LA -- so I'm using one.

LA 46,, 12.25 x 3.75!!!!!!!!!!

does it have ground clearance,,the 46 will swing the prop with authority,, should be fine
some of my uh,, lighter planes (?) have done well with that combination
ok so they were not much lighter

It really doesn't have enough ground clearance without reworking the LG -- so I'm going to start with 11" props and see how it goes.

[Tim Wescott]

I flew one flight today.  Short tank, speed was too high (4.8 second laps), but it seems to fly the same speed upside down as right side up.  Paul made this with unequal length leadouts, and I managed to make the lines not quite accommodate this, so I need to make some extra-short and some extra-long line clips (and I managed to get my oh-so-carefully thought out marking scheme backwards, so the "up" line is marked the way I usually mark "down").

The CG seems about right, although I may fiddle with it down the road.

[bill bischoff]

Put your lines on according to your own "up" and "down" markings. One line should now be decidedly too long. Just shorten that line as required, and all will be well.

[Randy Powell]

So Tim, much different that your last ride?

[Tim Wescott]

Put your lines on according to your own "up" and "down" markings. One line should now be decidedly too long. Just shorten that line as required, and all will be well.

Certainly I'll do that if I need to shorten the lines.  For now I'm going to stick with what I have -- I may put some white heat-shrink tubing on the "up" line, and make an extra-short line clip.

So Tim, much different that your last ride?

From what little I could tell in one short flight -- yes.  I was not on top of my game today from a combination of allergies and having to get up two hours early to help #2 son get to a school function so I didn't want to get aggressive with the plane.

[Randy Cuberly]

Hmmmmm... A64 oz airplane with an LA46!  My guess is that it's going to need to fly fairly FAST!

Short Lines???

It is pretty!

Randy Cuberly 

[Tim Wescott]

Hmmmmm... A64 oz airplane with an LA46!  My guess is that it's going to need to fly fairly FAST!

Short Lines???

It is pretty!

Randy Cuberly 

Paul said use a 46LA.  So I'm using a 46LA.  You can't say "no" to Paul (and besides, it's an interesting experiment).  It's on 65' lines, probably over 68' from handle to fuse center.  I can't make them much longer!  I'll see how it does when it's slowed down, but I think I'm going to like it.

Why do you think that it needs to fly fast?  It has 680 square inches of area outside the fuselage -- 700 if you calculate it the usual modeler's way.  It's got ten percent less wing loading than my Twister.  From that point of view it should be happy flying slower.

[Randy Cuberly]

Paul said use a 46LA.  So I'm using a 46LA.  You can't say "no" to Paul (and besides, it's an interesting experiment).  It's on 65' lines, probably over 68' from handle to fuse center.  I can't make them much longer!  I'll see how it does when it's slowed down, but I think I'm going to like it.

Why do you think that it needs to fly fast?  It has 680 square inches of area outside the fuselage -- 700 if you calculate it the usual modeler's way.  It's got ten percent less wing loading than my Twister.  From that point of view it should be happy flying slower.

It may have less wing loading than your Twister but it has significantly more drag also.   In vertical maneuvers and overhead I think thrust and acceleration are much more important than wing loading.  That means propeller size and efficiency and reserve torque to overcome the additional weight that the engine has to accellerate.  One way to maintain that balance between weight and accelleration is to maintain a slightly higher speed so that the mass decelleration of the aircraft doesn't drop below the  wing loading threshold for lift when the induced drag of the control surfaces is added during corners and tighter maneuvers especially in overhead maneuvers like the overhead eights and the top of the hourglass (that last corner at the top can be a killer for higher mass slower airplanes).  Can you spell accellerated stall!
I lost a 74 oz Trivial Pursuit exactly that way several years ago when I installed a new but not up to snuff yet RO Jett 65 and tried to nurse it through anyway!
More reserve ponies with a flat torque curve to maintain speed and accelleration up there is critical!

I'm not saying that the LA46 is a bad choice for this application just that I believe it's probably at it's upper limit and and that is likely to make it more critical to deal with.

Randy Cuberly

[Tim Wescott]

Thanks for that Randy -- it articulates what was exceedingly vague in my head: that I need to approach this with caution and make sure that I understand the plane/engine combination as I go.

As it is, I have a handful of props that I'll be trying out to see which is best.

[Russell Shaffer]

It does help that you are near sea level. Just remember Randy's Salem experience.

[Mark Scarborough]

It does help that you are near sea level. Just remember Randy's Salem experience.

Randys Salem experience is why I quit flying sundayin Auburn,, my plane was hitting weird dead pockets,, sigh