N1EDM

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Hi,

I noticed that Horizon Hobbies is selling the Seagull Models PT-19, .40-sized. It looks like a fun type of airplane for a .52 4-stroke with a 60" Span.

I was wondering if anyone has built one, and what your comments are?

Does it have plastic parts or fiberglass? And, how is the airplane holding up?

Thanks

Bob

seagull extra

My Feedback: (12)

I built one last year. The cowl is fiberglass and in general the plane is very nice. I put a saito .82 in mine but if i had to do it over again I would have put one of my OS .52 surpass engines in it as it came out a little nose heavy with the .82 and I'm sure the .52 will have enough power for normal flying. Typical Seagull Plane ie. flys nice and a good value.

N1EDM

My Feedback: (2)

Thanks a lot for the input, SE. As a matter of fact, I have a Magnum 52 (OS 52 Clone) that I was thinking of using. You just helped to drive my decision.

What else did you like/not like about this plane? Any comments about things I should be watching out for during the build?

Bob

MercerAUST

I can't comment on Seagull O.40 size, but have built and flown the Seagull 120 size as well as the CPM 0.47 size (using a Saito 0.40 4-stroke). The build should be fine, make sure you bend the unbdercarraige wire so that the wheel axles are just in front of the leading edge of the wing (if necessary).

The PT-19 flies like any warbird, but is more benign than most because of its more generous wing and tail area. However, it is still prone to tipping on its nose during ground handling if the wheels are too far back. It will also drop a wing and spiral if you are going too slow (eg the stall is not benign). Definitely not a first or second plane, but fine after you have some experience.

I'm still flying the Seagull 120 size, but lost the smaller CPM when doing a level rudder turn counterbalanced by the aerollins. I lost too much speed and the plane tip stalled and spiralled into the ground. Not enough power or altitude to recoved from the stall and consequent spin.

N1EDM

My Feedback: (2)

Thanks for that information. I'll be sure to watch the angle of the LG - I've handled tippy planes before and it's no fun.

I don't forsee myself having any problems with it though. I'm an intermediate class pilot (he said, optomistically) so I should be able to handle it.

Thanks!!

Bob

top242

.... the best choice four strokes 52, or 56?

N1EDM

My Feedback: (2)

I've got a Magnum 52 set aside for this PT-19. It's a new engine - I just want to make sure that it can fly reliably while inverted. I have a Saito 56 but that's in another aircraft.

Bob

top242

Asp you think a 52 fs four strokes, is good for this plane?

N1EDM

My Feedback: (2)

I think that this Magnum 52 is going to be a good match for the plane. The plane is not that large, and I think I'll be putting on a 12x6 wood prop. I might use a Master Airscrew composite prop just for some 'scale effect'. But I think that the 52 is going to be just right for this bird.

I'm finding some shortcomings though. There was one spot in the instructions where you're joining the wings. THe instructions tell you to glue up the surfaces, press them together, apply the trim film, then use tape to hold the wings together while the glue dries. Obviously, you do NOT want to apply the Trim film at this point. The instruction is actually re-written a second time, after the wing has dried and the tape has been removed, right where the instruction should be. The first reference to the trim application should be ignored.

The elevator uses two pushrods and two servos - not a single pushrod. There are two problems with this. The ideal situation would be to join the elevators with a joiner wire and a single pushrod. Unfortunately, the two elevator pushrods are both 'sticky' in their sheathes. I'm not sure if it's because they're too large a diameter (.078 - a common size) or if the pushrod tube is too small a diameter. I think I will have to stick with using two elevator servos, each driving its own pushrod, and some .062 pushrod wires that will move more freely in the sheathes. Poor engineering, to my mind.

Does anyone have any other comments?

Bob

top242

Hello! in mine paste both stabilizers with a piano wire in a "U" and only use a servo to move the control surface.

My inquiry is in the air ...... this plane would go well with a four-stroke asp52FS?

N1EDM

My Feedback: (2)

Top, I hear you. That was my first idea. But my problem is that the elevator pushrods that I have are a snug fit into their sheathes. If they were a nice, slip fit I would use them in a heartbeat. But I will have to go down to .062 pushrods and I can't trust that to 'push' two elevators up without buckling, hence the reason that I'm staying with the two servos and pushrods.

What are you pushrods like? Are they snug or loose? Mine will move with a servo but they are snug enough that I don't feel that a single elevator servo will re-center itself without buzzing. There's just too much friction in my plane. I wonder if they're all like that.

Bob

top242

I repaired mine. When you reach that point I inform you

OzzyMark

Hi everyone - I've stalled the build on my Seagull PT-19 due to the elevator pushrod saga. Both the pushrods in my model are REALLY tight, and I haven't thought of a good fix yet.

If anyone has a solution I would love to hear it!!!!

BTW - I have a Saito .56 destined for the nose if this little plane

N1EDM

My Feedback: (2)

Hi Ozzy,

I still haven't found a fix yet myself. I am contemplating opening up the covering on the bottom and replacing the entire pushrod systems. THe funny thing is that the rudder setup is nice and loose/smooth. That pushrod binds in the elevator sleeves though.

Top, I'm also going to use a Magnum .52 4S in mine. But if I used a Y-wire to join the two elevators there will still be that drag problem. I'm kind of curious to see how sharp the bends are inside the fuse to cause all of this drag.

This sure is a disappointment. I just got off the line with HH. They say that they have no reports of anything like this for the .46 sized PT-19. He recommends that I cut into the fuse and straighten out the bends in the tubing. In a new airplane????

Also, he noted that the recommended servos were 90 oz/in JR's - a 90 oz/in servo for half an elevator in a .46 sized plane??? Yup, it's on the website under recommended equipment.

I'll cut into the fuse and put in my own pushrods but I don't think that I'll ever get another Seagull plane. And, my esteem for HH just went down a notch as well.

Bob

N1EDM

My Feedback: (2)

Seagull, you said that you built one and liked it.

Do you recall if you had a problem with binding pushrods for the elevator, and if so, how did you get around it?

Thanks,

Bob

OzzyMark

Hi N1EDM - thanks for the reply.

I can't believe HH want us to open up brand new planes to fix a manufacturing issue!! From the (limited) research I've done it would appear that the elevator pushrod drama is quite common in the PT-19. The rudder linkage is perfect in my plane - if
they could get that one right, why couldn't the get the elevator ones right too??

Shame really as otherwise it seems like a nice plane.

At the moment I'm contemplating putting two servos in the fuselage rear. The weight might not be a problem 'coz the Saito is quite a heavy motor, but I HATE having servos stuck out the sides.......


Any suggestions???


mark

N1EDM

My Feedback: (2)

Hi Ozzy,

If you can be patient, I might open the plane up today and have a look. I bought a some Sullivan Gold-n-Rods at the LHS yesterday. I'm going to remove just a little bit of the covering, enough to have a peek inside to see what's up with the pushrods and housings. I'll take photos if that's possible.

Bob

OzzyMark

Thanks heaps Bob!!!!

I'll wait for an update to this forum :-)



mark

N1EDM

My Feedback: (2)

I’ll preface all of this by saying that this is my own way of tackling this problem. I'm sure that there could be better ideas out there, but this appears to work for me. This doesn’t mean that somewhere down the line I’m going to come up with a “Duh” moment and realize that this was all a bad idea. So, for anyone wanting to duplicate my method, Caveat Emptor.

I started by cutting the covering in two open two bays on the bottom. By some stroke of luck, I picked the two bays that would serve me best.

In the picture you will see four control sleeves (remember, you’re looking at the bottom of the fuse). The two top sleeves, the yellow and the top clear one, are for the antenna and the rudder respectively. The two bottom ones are the ones that we are interested in.

I decided that there was not a simple smoking-gun solution to this, just poor engineering in the placement of the supports for the outer elevator control sleeves. They could have been laid out in a straighter line. My decision was to replace the existing sleeves with a Sullivan Gold ‘n Rod setup. One setup would be enough for two sleeves (more later).

The existing sleeves are held in with the proverbial hot melt adhesive. For once, that worked in my/our favor. I was able to peel back the adhesive from the inner bulkheads. . It came off pretty easily using a large X-Acto knife and a pair of needle-nose pliers.

N1EDM

My Feedback: (2)

The sleeves that I used are from a Sullivan Gold ‘n Rod #503 Control Rod Set. There are two to the set and I only needed the outer and inner sleeve from one control rod set, by the way. The Sullivan outer rod is about 1/32" smaller in diameter than the original used in the plane so that's a break in our favor. The new sleeves will slip in with room (albeit small) to spare and I didn't have to hog out any holes for proper fit.

The outer rod was cut into two 16” pieces. Thread it through the original holes and make sure that the aft portion of the outer sleeve projects only about ½” through the aft bulkhead. Don’t go too far here or you’ll get into trouble that you will have a hard time getting out of..

Mark the rods where they pass through each bulkhead, take them out, buff them with sandpaper and reinstall them. Epoxy them in place.

Note the orientation of how the rods cross each other in the photo. Orientation DOES make a difference where they pass through the center bulkhead. If you dry fit everything just to be sure before gluing the outer sleeves in place you'll see what I mean. Don't make the mistake that I almost made.

I also did a little work on the Servo mounts. They are a very snug fit for the S3004’s and S148 that I’ll be using for the elevator, rudder and throttle, respectively. I trimmed around the mount a little for clearance.

I’m going to leave everything here for now to let the epoxy dry. I still have to work on my J-3 Cub for tomorrow but my plan is to continue this tomorrow (late in the day, it’s supposed to be too good for flying to not take advantage of it). I’ll show my intended plan for making the control hookups.

For the record of any lurkers reading this thread, I've already assembled the wing and, so far, there were no surprises.

By the way, I haven't read through the entire manual yet, but in thumbing through it I could not find a use for those two pieces (one lite ply, one balsa) that are strapped to the receiver/servo tray. Can anyone tell me what they're used for? Were they mentioned in the instructions?

Bob

N1EDM

My Feedback: (2)

I tried getting in earlier but no luck. I'll give it a try now...

My hookup is going to be a bit unconventional for reasons that will be explained in the next msg.

For the servo end, I'm using a Clevis threaded on to a 2-56 'stud' for want of a better description. To size the inner rod, I only projected it about 1/2" beyond the aft bulkhead, about even with the end of the outer sheath. If I go too far, it's going to cause problems I used .072 wire with a 2-56 thread, about 2-1/2" long. I first inserted the unthreaded portion into the inner rod (for a bit of stiffness) and threaded the threaded portion about halfway into the inner rod. The photo shows the 'stud' and the way I attached it. Then, there is a photo of the finished installation.

N1EDM

My Feedback: (2)

Now for the unconventional part - As you can see, there is ony a narrow slot coming through the fuse. I thought that if I put through a piece of bare wire and soldered on a clevis, the heat that close to the fuse might cause some problems. So, I will thread a piece of threaded .072 wire into the inner sleeve and run that through the slot. Then, I will put a 90-degree bend in the wire and hold it on with a keeper. I figure that if it works on a servo horn, it should work on the control horn too, though the horn will have to be drilled out. IT's not elegant, and I will put some silicone tubing on it to hold the keeper to the wire.

The piece that I show in this photo is for mock-up only. I estimate that the piece will be about 4-1/2" but haven't fixtured the tail pieces on yet, so I don't have a real number. The photo is for demonstration purposes only.

Other than this, it will require opening up the slot a lot more than I want to. But if this method does not work, that will be my 'plan B'.

Whaddaya think?

Bob

OzzyMark

Looks good Bob!!

I've got a friend pickup me up some linkages etc from Perth (we're 7.5 hours by road from the capital city....).

I'll have a bash at it when Kim gets back. Just a shame that a new plane needs such extensive "modification" to make it work.......


mark

N1EDM

My Feedback: (2)

I feel the same way, Mark. I can see where one can be expected to make minor modifications or improvements, but one should not have to tear off covering and replace key components for this to fly correctly.

I may modify my decision a little bit. I might use the solder clevises after all but I have to think that through a little more. I'll let you know when I do it. Do you have any thoughts on the matter?

I'm going to try to balance the plane before I cover up the bottom of the fuse. If the plane is tail heavy, I might just go with one linkage and a U-wire to hold the two elevators together. If not, I will leave things the way that they are, i.e., two servos and two linkages. Hmmmmm, with that setup, if you decided that you wanted to experiment a little bit (and risk your plane) you could turn the elevators into elevons and couple those to the ailerons... I wonder what the plane would do then!!

Bob

OzzyMark

G'day Bob

The 0.062" control rods seem to have worked for me. One is a little tighter than I would like, but I think it will be OK with some soap or something.

I'm not sure I'll buy another Seagull plane if this is an indication of the build quality - it may not be a really expensive model, but the quality should be better than this.

Do any of the Seagull Models or Horizon Hobby rep's frequent RC Universe?? I'd be interested in their take on this......


Thanks for the help and advice - see you in the sky!!!!!


mark