The plane balances just ahead of the cg without the gear and battery so I decided to mount the battery a bit further aft than recommended. A 1/8 balsa tray and velcro strap fit perfectly in the open bay just behind the wing. I added decals and am now just waiting on the gear to arrive. I doubt if I will need much if any tail weight. The weight is now 5lb 1.5oz and I have 2.5oz in landing gear and a switch to add...maybe 4.5oz total.

I got the new carbon gear from Hobby City. They are great quality,very light and a little taller than the stock gear. The plane balanced at about 125mm from the LE, 8mm behind the "ideal CG" in the manual. These things are usually conservative so I decided to fly it as is. The total weight was 5lbs 5.5oz. This after saving at least 7oz so AB models is way off in the weight estimate. Still, that's not too bad for 538sq ins.

We had great weather today (for Canada...12C and 10mph winds in March!!) so we headed out for the test flight.

Even at the relatively aft CG the plane tended to nose over on take off roll. The soggy ground and small wheels and increased sweep back of the new gear did'nt help, but the take off roll was straight and climb out very positve and needed little to no rudder. A click or two of down elevator, left aileron and rudder and it was trimmed. Not bad for an AFR that had a few "straighness" issues.

I dont think the CG is too aft at this location but it is pretty neutral...maybe a bit too much so. 117mm from the LE may really be better.

With no mixing, KE flight with left rudder is just about perfect though it pitched to the top a little with right rudder. Downlines are straight with only a slight pull out. Uplines require a little left rudder....I think the right wing is heavy or it's got too much right thrust for my liking. Inverted needs just a little push. The plane slows nicely for landings but you run out of elevator control as it slows. I think the stab is undersized.

With a 12-5 on the OS50 the plane has to be flown fast or you run out of vertical, engine screams like crazy even though it's rich (I should have tacked it). We'll try a 12-6 tomorrow.

Generally I think there's lots of potential for pratice up to advanced but it will need more grunt or will have to be flown fast. We'll experiment with props until we get the best performance.

We put 4 flights on it today. My son (10) flew all but the trim flight and is thrilled with his first Pattern plane.

do you guys think the jett 90lx will to much for this plane?

The plane looks really good! Glad it flies nice.

I had/have a similar issue with the Venus 40. I was running a .46 engine with a 12x5 prop, and it simply ran out of vertical even when flying wide open into the pull (tached on the ground at 12,000). I switched to a .55 engine so I could turn a higher pitched prop. Going to try a 12x7-8.

Good luck and keep us posted.

Does any one know where i can find a motor mount like the one was in the pasckage of spot on ;

Weezle, a 90 will be way too much for this. You will not be able to balance near the required CG. I think the OS55 would be the best 2C for this and a ys63 would be the best 4C.

The motor mount is very similar to a dubro adjustable mount...maybe 60size.

Colin.

Final update....

The carbon gear from Hoby City was swept back a bit too far and made take offs and landing on tall grass difficult as the plane would usually nose over. I found the perfect replacement in the3DHobbyshop 55" Edge gear. It's even lighter than the hobby city gear.

The performance with the 12-6 was not very good either so we went back to 12-5. I think we originally ran the engine too lean so this time it was set just 3-4 clicks in from very rich (4-cycling) and tached at 12.2K. At that setting the plane has very good vertical performance, slow downlines and good speed.

I took a little right thrust out and added 5gms to the left wing. Uplines are now very straight, loops need almost no rudder.

Rolling is very axial with 0 differential, snaps are super fast but are bit too deep....we are going to reduce the aileron and elevator to fix that.

The overall performance is exceptional for a 50 size pattern plane.

Colin

Colin,</p>

Isn't that gear a one piece unit? If it's the one I found on their website, how did you make it fitwith a band saw??</p>

I've flown mine a few times &amp; agree with you that it's a great flying plane for a 50 size. I needed some tailweight on mineprobably 'cause it has an OS 70 up front...</p>

Kevin</p>

Yes, it's a one piece gear that I cut using a Dremel.

You can avoid the tail weight if you replace the gear. The 3DHS gear was only 38gms before I cut it.

Colin

Hi

I got a ys-63 and I also got already a spot on 50 with a saito 82. My question is if I should get another spot on for the ys or try a different plane like a groovy 50?

Happy Landings

I would'nt bother with the groovy unless your interest is 3-D/Freestyle.....anything other than pattern.

I would put the YS63 in the Spot on. The 63 is lighter and more powerful than Saito and would allow you to turn 13" props. It would improve the speed control.

If you're looking for another airframe for the YS63 I would look at the Osmose 70. I have'nt flown one so I don't know if its better but it sure looks great.

Colin.

Thank you for your comments. I was thinking of the pattern version for the groovy F3A.

Happy Landings

Hello guys, I have been following this thread with quite a bit of interest as it has rekindled my interest in the Groovy 50 F3A which I have sitting in the basement. I believe that the planes are very similar and I am starting to think that I might have put the Groovy into mothballs a little too soon.

I just have a quick question. I would like to get an idea of what props are being used on the Spot On as well as what RPM's are being achieved. My Groovy is an electric conversion and I want to get a sense of whether I am in the ball park or not. The power system I was going to put on the plane will spin a 13x10 prop at about 7700 rpm giving me a pitch speed of about 72 mph and about 130 oz of thrust. The plane weighs about 95 oz. The input power is of about 650 watts. The set up is geared and I can change the ratios to either turn a bigger prop or to get higher RPM and power.

Just for reference, a 12x5 prop spining at 12K RPM requires close to 1000 input watts (850 watts at the prop) and generates a pitch speed of about 58 mph and about 127 oz of thrust. My set up will generate about the same amount of thrust, but at a somewhat higher pitch speed. Any one using higher pitched or larger props?

Any input would be appreciated.

Thanks,

Teo

Hi all, I was just wondering if anyone could help me out. I crashed my spot on 50 yesterday, and broke the wing. Does anyone know if world models sells spare parts for these planes ?? I have looked around on the net not had much luck If so where would I be able to buy a wing from
Regards Mark

Try here:

http://www.airborne-models.com/html/...?ProductID=111

The wing is $75 US, and the whole plane is only $140. Don't know how much shipping would be from the US.

Thanks very much for the help John, I have sent them an e-mail to find out the cost of the wing shipped to Australia ,the only other thing I need to work out is if the plane is a spot on 50 N or R. I bought the plane already built up and I can no longer contact the chap I bought it off so I don't know whether it was a N or a R . Maybe somebody on the forum might know how to distinguish the difference if there is any?? In the wing
Regards Mark

One version has the muffler tunnel area fitted with a fibreglass half tube, the other has an open bay better suited to 4C mufflers.

I can't recall which is which. They (the US distributor) were pretty good with answering emails....give them a try.

Colin.

Thanks for all the help Colin and John
I got a e-mail back from AirBorne Models this was their reply.
The N version has some modification at the exhaust channel area and make it more suitable for mounting short pipes, R is more for stock muffler.
The wings are the same for both R and N version.
They have referred to my request for a wing to their Hong Kong office has shipping from their to Australia should be cheaper
Thanks again for all your help regards Mark

Be careful that you do not have the original version...just the Spot On 50. In the original version, the leading edge of the wing which mate onto the fuse is tapered. In the R and N versions, they squared this area off so the front of the wing has a square "butt" up to the fuse. Also, the belly pan on the original version had to be glued onto the wing, the N and R now have the two guide pins going into the fuse.

Just a question Colin:

how much right thrust do you think is ok for this plane?

Happy Landings

Luis

The right thrust is built into the firewall....I didnt measure it. After a few flights I added washers behind the engine mount to reduce it a little. I think the right thrust provided may be OK for a 4-stroke turning 13" props. Whatever engine you are running you'll have to try it and see if you like it before making any changes.

Hope that helps.
Colin.

Can you give me measurement of both the original gear and the replacemsnt gear? I'm putting a Spot On together and will need clearance for 14" prop.

Thanks

The gear from 3D Hobby shop that we are using has just about the same dimensions as the stock gear. I think they are around 140-150 mm high. Neither will accomodate 14" props with much additional space. However, there are lots of other choices out there...you just have to dig a little. 3DHS has a ton of them...I'm sure one will give adequate clearance. Maybe the AJ Slick gear.

If you get something taller just avoid sweep as the plane will tip over at the nominal CG.

Colin.

Hello,

I am using the same gear that collin suggested on a Groovy 50 (the Spot-On's predecessor) and flying it an as electric plane. My current prop of choice is a 14x12 and the landing gear does provide sufficient clearance. Keep in mind that since I fly off a grass field, I am also using slightly larger wheels as well (2.5" I believe).

Good luck,

Teo

Thanks Teo, I too fly off a grass field. Looks like new gear and tires for me.....