3rd flight on GP spacewalker I finally assembled, no fun in windy conditions ! I need advice what to about wing incidence issue when using saito 120, I have the ballooning problem others have experienced. I added 2 deg. downthrust on engine, still just does not feel right.

Plane setup is saito 120, throttle servo in engine compartment, upgraded to 440 linkage, pull pull rudder, balanced out about 4 inches , a little nose heavy. I wonder if I should use a smaller engine or change wing incidence? next question is if I change incedence should I move dowel location and have to deal with gap at front of wing or remove material out of saddle and move rear of wing up?

The 120 probably is an overkill but others have had to add so much weight up front and I sure hate to do that, and I had other plans for my saito 100. I know this can be a good flying plane but the way it is I'm sure not impressed with it. I'm much more impressed with my supersportster 60 and my Fontana 90. Any advice from others with more experience sure will be appreciated!

The GP Spacewalker is a great flying Plane, and I think mine handles the wind rather well. I have a Saito 100 in mine with fiberglass gear moved forward just in front of the wing, and about 9 oz of lead in the nose. So actually the heavier 120 Saito should help you to eliminate some of the dead weight in the nose. You also mention the Super Sportster, and I have that one as well, except mine is the discontinued 90 size Super Sportster(See Photos-One with it on the field and one with it hanging on the back wall)). This is also a great flying Plane, but its flying characteristics are quite a bit different than the Spacewalker IMO. I really don't know what advice to give, except to say that I think if you give the Spacewalker a bit more time in the air you might eventually come to the conclusion that it is actually a great flying Plane with its own flying style, and not really to be compared to the Super Sportster. Good Luck.

I have experienced the same climb tendency on
my H9 Texan and I reduced the wing incidence.
AT-6 Texan then became a straight flying good plane.

Tsutomu Mabuchi

Have a Saito 91 and flying it for 3 + years. Great airplane. Could possible exchange it for my 100 but no more than that. Had to put in 8 oz lead in front.
Only thing I am going to do different is fix the landing gear with a bungee set up.
This is not a 3d or pattern airplane but my best enjoyable flier. On windy days landing must be on the main with a little power then bleed off speed and drop the tail.
Very realistic flier. Still learning to do a SLOW roll smoothly
Bill

Thanks for the replies, I flew it again this eve. not quite as windy as last eve. I give the graphtec gear a shock test and it passed. I'm no expert pilot but I normally can get decent landings but this plane is the most squirrelly thing I have ever flown, I think it is too nose heavy and too overpowered. I have a Thunder Tiger 90 4 stroke I tried on the F90, will put it on the spacewalker and try that. I think some planes can use a larger than recommended engine and work fine but maybe not the spacewalker. The wing fits the fuse perfectly, if I mess with the incidence then I have to deal with that issue. I spent more time building this plane then any other and it sure is dissapointing but Ill get it right!

I had a GP Spacewalker for 3 years. It started out with a Saito 100, not enough power, too hard on fuel and would balloon like crazy. Replaced the 100 with an OS 120 and all my problems went away, lots of power, used 1/2 the fuel and the ballooning went away. I have heard that these planes work much better nose heavy and I think that is why my ballooning went away. I never touched my wing incidence and saw no reason that I should.

You DO NOT have too much power, try a bit more nose weight and see what happens. This plane does not fly very well in windy conditions, anything over 10 mph, mine stayed on the ground. Good luck I wish I had mine back - forgot to charge the #@*&$ battery. [&o][&o][&o]

P.S. I found this plane very hard to slow down for a landing, it just kept floating & floating. I had to install an onboard glow driver in order to slow the prop enough to land anywhere near gentle and then sometimes I just cut the engine once I was committed. People laugh at me when I say this, but I found this plane very challanging to land properly and I've been at it a loooooog time. But once I got onto it and installed the 120 it became one of my favourite flyers - just not in the wind.

Are we all talking about the same GP Spacewalker? I have flown mine in fairly windy conditions, and felt pretty comfortable with it. I also fly mine with a Saito 100 with 9 oz of lead in the nose, and fiber gear has been added just in front of the wing. I also run oversized 4" tires on mine and it handles the grass field like a dream. I always take off on a slow roll, and then I like to really crank the throttle and run down the entire length of the runway with the tail up, and pull her up at the last minute even though I could have taken off the ground 150ft back. What I am trying to say is that I really feel comfortable with the way mine handles on the ground, and don't hurry getting it airborn. I just don't know what to say here..............I think my GP Spacewalker is a cream puff on the ground and in the air. As stated above, there may be something to having plenty of weight up front, because I do use a 16 oz tank for the thirsty Saito 100, which would also make her pretty heavy towards the nose with a full tank. I average about 12-15 minute flying times with this combo. The only real good advice I can give is not to give up on it, because it really is a great flying Plane.

SPECS FOR SAITO 100

Type: 4-stroke
Displacement: 1.10 cu in (17.10 cc)
Bore: 1.14 in (29.0 mm)
Stroke: 1.02 in (26.0 mm)
Cylinders: Single - Chrome Plated
Total Weight: 20.9 oz
Engine (Only) Weight: 19.5 oz
Muffler Weight: 1.4 oz
Crankshaft Threads: 8x1.25mm
Benchmark Prop: 14 x 8 APC
Prop Range: 13x9 - 14x10
RPM Range: 2,000 - 11,000
Fuel: 10%-30% Synthetic
Mounting Dimensions: 115 x 60 x 128 mm
Muffler Type: Cast
HP: 1.8
Cylinder Type: AAC
Carb Type: Barrel, 2 Needle Valve Type: 4-stroke

If you notice the total weight with the muffler for the Saito 100 is 20.9oz with a power output of 1.8hp. That is an awesome power to weight ratio when compared to the O.S Surpass 120 with a total weight of 33oz , but with a disapointing 1.9hp when compared to the lighter and smaller Saito. The O.S 120 only outpowers the Saito 100 by .1hp, but the O.S is more than 12oz heavier. I am not trying to say Saito is better than O.S or vice versa, or start an arguement. What I am trying to say is that if you use the Saito 100, and use 9oz of lead in the nose that you would still be lighter than the O.S 120 that only has a very small fraction more power according to specs. Just some food for thought.

SPECS FOR SAITO 120

Type: 4-stroke
Displacement: 1.20 cu in (20.00 cc)
Bore: 1.26 in (32.00 mm)
Stroke: 0.97 in (24.80 mm)
Cylinders: Single - Chrome Plated
Engine (Only) Weight: 28 oz
Crankshaft Threads: M8 x 1.25mm
Benchmark Prop: 15x8 APC @ 9,000
Prop Range: 14x8 - 16x10
RPM Range: 2,000 - 11,000
Fuel: 10%-30% Synthetic
Mounting Dimensions: 138 x 69 x 133 mm
Muffler Type: Cast
HP: 2.2
Cylinder Type: AAC
Carb Type: Barrel, 2 Needle Valve
Crank Type: Ball Bearing

The Saito 120 comes a full 5oz lighter than the O.S 120, and with a much higher output rating of 2.2HP compared to the O.S 120 Surpass with 1.9HP. Again I am not trying to start an arguement, but just wanted to give you something to think about in regards to varying engine weights for your spacewalker, and what kind of power to expect if you decide to try something else in your spacewalker. IMO, I think the Saito 120 would be great in the Spacewalker, but rotational torque of that strong engine may effect handling in several ways. Just more food for thought.

You can say what you want Saito 100 vs. OS 120 all I can tell you is my SW went from a very poorly powered, fuel guzzling plane to a nicely powered, fuel sipping sweetheart when I changed. Here are my observed specs.

Saito 100

Prop - 15 - 6 APC
RPM's 9200
Fuel for 10 min. flight - 15 ozs.

OS 120

Prop - 15 - 8 APC
RPM 9500
Fuel for 10 min. flight - 10 oz.

9200 on a 15 - 6 vs. 9500 on a 15 - 8 is a HUGE difference in the real world.

The weight didn't matter spit in this plane, actually it helped.

Besides my intention was not to start a Saito vs. OS war ( I fly OS, YS & Saito ) I was just trying to point out that his plane was NOT overpowered.

Don, I appoligize if it seemed like I was trying to make one out to be better than the other. This was not my intention. We were discussing the weight that the Spacewalker needs inside its nose, and I was just pointing out options to consider when deciding what would be a good weight of engine to use, and what kind of power to expect if you either add weight with a certain engine, or lose weight. So please don't take my post as an O.S bash. I also own O.S engines, Magnum Engines, and Saito Engines. I have no problem with any of the ones I have. Another thing I was trying to point out was that it don't hurt to add a little dead weight if needed when using the Saito engine, because they are lighter, yet still have plenty of power. I am sure your O.S 120 does a great job in your Spacewalker, and again I appoligize if I sounded like I was bashing it.

Apology accepted

Way too windy again here in Oh. but could not resist another test flight, changed prop from 16x4W to 15x8 and it seemed better, only one beep of down-trim! I bounced a little on landing, just so hard getting used to the way this plane floats and floats on landing, even into the wind. The 120 will be OK thanks for all the advice and help. I'm going to glass the inside of cowl and repaint it so it matches the covering and put the wheel pants on. Its time to get on with the next project.

Just bought a second hand GP SpaceWalker with a Tower 75. I also find this plane a bear to land. The biggest problem, besides the floating which I can compensate for most of the time, is weathercocking in a crosswind landing. As the plane slows down for landing, even in a slight nose down attitude, the plane will fly into the wind. This has caused some scary situations especially for pilots flying upwind from me. It seems that although it is balanced per the manual that adding weight to the nose might help. Thoughts anyone?

I fly my GP Spacewalker in all kinds of wind, and crosswinds are no trouble. The plane has a mag 91 4 stroke on it that replaced the Saito 100 with 9oz of lead in the nose. The Plane also has a big Woody doll in the cockpit. That Plane with that big ole thick wing really likes the weight. You are not going to 3D this type of Plane, and basically just want it to handle well. So my advice is to load it down some, and put it slightly heavy to the nose. Even with the extra weight, my Spacewalker has never even showed the slightest signs of tip stalling on a slow landing. It does weathervane a little in a crosswind, but a little rudder control takes it right out.

Sounds like good advice. I will first triple check the CG, and then, if it is not already, add a few ounces to make it a bit nose heavy. Maybe the added weight will steady it down in the wind, reduce the floating and at least reduce the biggest problem for me, weather cocking in a crosswind landing. Here's hoping.

Thanks

ckangaroo70:

Checked balance again using a better method. Plane was tail heavy. Added 6 ounces of weight to the firewall so that the plane is now a bit nose heavy.

Floating (ballooning) on landing has basically disappeared. Weather vaining is still there, but much more controllable now that the ballooning is gone.

Thanks for your help.

That is great news! The Spacewalker really does not seem to mind the extra weight, and in fact it really improves its handling IMO. For most Planes people are always trying to shed as much weight as possible, but with the Spacewalker it flys best a little heavy, and and especially heavy to the nose. Hope you have lots of good flights with it![8D]

Can someone please let me know how to measure the center of gravity ...i have had this plane for years and have missed placed the instruction man.

Thanks so much

-john

If I remember right...it jut balances on the main spar.However you may want to get another opinion just in case my memory isn,t to good.

I had the .40 Seagull(?) version with an AX .46 engine. I did not note a climb tendancy with this setup, though my plane did come out heavier than I expected.

Because of the long tail and tall rudder, it did tend to weathervane in winds, but you learn to deal with this ( up to a point ).

I had A GP spacewalker with a saito 100 in it, it too would balloon when power was applied, and was not fun to fly, I checked the wing incidence and found it to be 3 1/2 positive too much in my opinion so I reduced it down to about 1/2 positive and I could not believe the difference it made, no more ballooning it flew like it was on rails.