Seagull Pilatus PC9

[Ian Jones]

I've had two of these and know of two others. All flew much better and could be glided in for a slower landing by setting the CG back 10mm further than stated in the instructions, i.e. 90mm. My first PC9 and one other I know of crashed becuase the elevator horn sheared of at it's root so consider beefing that up. All were great to fly.

[David Ashby - Moderator]

Steve enjoyed the review - watch out for a dedicated electric version soon - this looked lovely at the Nuremburg toy fair.

[Pete Norris]

i had one she was dream to fly i put a 58 mds on the front no worrys about c.g flown out of the box

[Ian Jones]

Mine flew fine out of the box too but the landings were much improved by the slight adjustment and it didn't compromise the general handling of the aircraft.

[Peter Harrington]

My PC9 has been built as per the instructions, the C of G could be set back slightly but i have left it. I would recommend this great model as a follow up to the faithful high wing trainer. Looks the the biz, take offs and landings are a breeze.

[Phil Winks]

now then looks a peach but does any one make an electrikery version I wonder

[Ian Jones]

Yup - Seagull of all people!

It's a little smaller but looks nearly as good. The build is very good but quite a lot lighter so don't expect it to be as robust.

[Phil Winks]

Thanks Ian must look that up

[dennis comeau]

 Steve hi. Have just read your review that you done on the Seagull PC9. I have put a thread on the forum re. the Cof G with this model. My question was, having balanced the model as per the manual, ie. upside down, and putting approx. 200grms. behind the firewall, achieving good balance, i have found that when i turn the model upright it is nose heavy when held at the balancing position. Is this normal. As a newie i am a little confused with this and although i have had a couple of responces are not to sure. By the way, power unit is a SCfs52 inverted. Any help much appreciated DC.   

[Ian Jones]

There is no doubt that it is easier to balance a low winger inverted - it's just like balancing a high wing aeroplane that way, so I don't know why you checked it again upright. Might turn out to have revealed a problem all the same. My thoughts for what they are worth:

• I'm surprised that with a highly suitable OS FS52 upfront that you had to add a massive 200 grammes (600 grammes in one of your other messages) to the FRONT to balance it. I have had to add weight to the rear these aeroplanes before but never to the front
• Are you sure that you have used exactly the same points for the inverted and upright CG checks you carried out?
• It seems to me that you could have measured too short a distance from the leading edge when balancing it inverted. (instructions say to balance it 80mm from the leading edge at the wing root, though I use 90mm - see my posts above)
• Get someone experienced to double check it before you commit to the air. If that 200 grammes stays on and I'm right about it being a seriously nose heavy then it might not even get off the ground but if it does then when trying to fly at low speed (ie stall testing & landing) it might end up in the ground! Whatever weight is on the front has to be capable of being levered on the cg point by the elevators - if they can't do that then the aeroplane will not pull out of a dive, fly at low speed or flare for landing. Slightly nose heavy is ok, seriously nose heavy will kill an aircraft just as surely as being tail heavy - best solution is to be patient and get get it just right and as I said before flying get it checked by an experienced hand.

Please let us know how you go on I'd be very interested to find out the result.

Bye, Ian

[dennis comeau]

   Hi Ian. Many thanks for your advice. Yes i mistakenly put 600grms on  the other thread, should have said 200. Anyway i did use same distances when measuring and result was as i said , inverted, aok, but when upright nose heavy.  Steve,s original revue of the model i believe mentioned on one model that he  had to add 300grms to the front end albeit with a lighter engine. I will double check to be sure that i am correct  and not risking a nice model.   

[Djay]

I have one of these, and have put mechanical retracts on it, with a 3 blade propeller, and OS 50 up front.

It looks nice in the air with the gear up and is a very gentle flyer.

[Ian Jones]

So Djay you've improved an already good model! Must look great against the blue sy of Dubai!

Dennis - as long as it balances inverted it should be OK - hope all goes well.

[Garry G]

I had  a PC9, sadly no longer hanging up in the shed, fitted with an ASP 46 which would not run consistently. it would hunt at full throttle and spray loads of fuel out of the muffler. In desperation I cut out the lightply cross bar that set the tank height and lowered the tank. This seemed to help.

Anyone else had similar problems with tank positioning?

[Ian Jones]

Oh Garry, glad you mentioned that, I'd forgotten all about it. In the versions I have had there had been a dowel rod behined the bulkhead to support the tank. I removed it both times and the effect was to reduce siphoning of the fuel, especially at low throttle when the excess fuel cools the plug and the causes the engine to stop. The wet plug then making it difficult to restart.

This is a common problem with inverted engines and I know Just Engines recommend having the engine at an angle becuase that advice from them once appeared in RCM&E. I can't remember what, if any, minimum angle was recomended though.

Anyway, I have run my PC9s for 4 years with an inverted Irvine 46 and apart from the occasional tuning problem the inverted engine hasn't been so much trouble to make attempt any further butchery to try and fix it.

[Garry G]

Hi Ian, if my memory  serves me correct an earlier version of the PC9 I had did have a dowel at the front but I can't remember if I altered it, I know I didn't have any engine problems, just my love of flying into trees that wrote that one off.

A couple of other club members have mounted the engine sideways and also 45 deg. from vertical and they have no problems. I just didn't like the idea of butchering that rather nice cowl.

 Thinking of getting an electric version !

[Ian Jones]

Hi Garry,

That's interesting - I've got a spare cowl so I just might try rotating the engine.

Perhaps flying into trees should be a sport in itself, it could be quite competitive.

Have you seen the electric version? Nothing wrong with it except that it's a little smaller and a lighter build. I haven't seen one fly.

[jimmac]

Hi Dennis when you balanced the model upside down did you get the model to balance slightly nose up or down,remember you have balanced it inverted so you would be looking for the nose to be slightly nose up on your cof g position.

                   Cheers Jim.

[Tim Mackey]

Old thread I know, but just notiuced the last posting - that aint right.

Upside down or not, if the nose dips its nose heavy, and inverting it makes no difference to where the weight is surely!

[Ian Jones]

OOh! dead right Tim.

 

Fortunately this aircraft is tolerant to being very slighty tail heavy as the stated CG point is quite conservative. I know this because I did it on purpose with two of mine and it improved take-off & landing (Shorter take off run, slower landing as a result of the elevator being able to function better at low speeds).

 

Any more than very slightly tail heavy and it will bite though!

 

Ian

[Tim Mackey]

I had my "old" one at 85mm from L/E ( the larger .120 size model ) and although she was fine, I felt it was ever so slightly pitchy, so I have the new one at 80 mm.

[Shane Sunday]

I am so glad I found this thread. Having read the review and much research otherwise before purchasing my PC-9 I felt confident this would be a sprightly follow on from my Jitterbug. I wanted a JUG but I need to be realistic about my abilities. I purchased the IC version and quickly converted it to leccy. I also took all the bits and bobs from the box and piled everything on the scale. She came in at 5lbs 7oz unassembled. I plan on powering it with a 5s 4600 mah lipo and motocalc says I'll get 7-8 min flight times useing a 11x7e prop on my Turnigy 4250/ 700.

 

Initially I wanted to use a 4 cell lipo as I have lots of 2cells kicking around but after bench testing the setup I got 18 amps and 404 watts. No where near enough to power this thing. So motocalc got that wrong. No worries. The 5cell 4300 mah lipo adds 620 grams to the equation but puts out 38amps and 665 watts continuous. Not too bad me thinks. Now I run into my problem about where to put my battery hatch and how to cut it? There aren't too many formers on top of the forward fuse and it's a bit tight anyhow. The bottom just before the fire wall looks appealing bit I'm unsure if I risk dumping my lipos mid flight. As well that motor is a big lump starting off heavier than the OS 40 FS I have kicking around in the shed collecting dust. Hell even with the dust it feels lighter. So now I plan on adding 620grams worth of power to the nose?????

 

 

Sorry this is so long but does anyone have any suggestions that could help me before I get into cutting wood please?

[Tim Mackey]

Cant help a lot here Shane - mine is the bigger .120 sized version, and came ready adapted to take electric power with a preformed top hatch for battery access - could you not do similar?

[Ian Jones]

 

"As well that motor is a big lump starting off heavier than the OS 40 FS I have kicking around in the shed collecting dust. Hell even with the dust it feels lighter. So now I plan on adding 620grams worth of power to the nose?????"

 

This probably isn't the way you want to build it Shane but with so many unknowns I'd be inclined to do everything else before deciding where the battery goes.

 

That way you can assemble it, invert it and move the battery backwards & forwards to find the correct balance.

 

It might make for some tricky & fiddly cutting but if I've understood correctly it's possible that you might want your battery behind the CG point to balance the aeroplane. From that you would then be able to condiser your battery hatch options. You may be able to fasten the canopy to the cockpit and make the whole removable. If that did happen the you would have a very accesible opening, might need some bracing though.

 

Ian

[Shane Sunday]

Well guys in the end I have made a top hatch just behind the fire wall and leading to just in front of the canopy. I bought 2 5s 5500mah lipo's and still she is tail heavy! sure I don't put both in at the same time. The recommended CoG is 8-9.5 cm from the leading edge at the fuse right? I've asked a friend of mine and he assures me this is the case although the manual, by the looks of it, is telling me that I measure 8-9.5 cm from the leading edge at the wing tip? this makes the CoG almost centred on the wing. So with the lipo in and weighing a fair bit at 620g it still looks as if she is going to need some lead up front.

 

When I built the hatch I marked out with tape where I wanted to cut, made sure she was straight then took my razor saw and gently started sawing. I then built 4 formers to keep the curved shape 2 for the front and 2 for the canopy side. I then made hinges for one side and magnet mounts for the other side. I wanted to have the mounts going lengthwise but then the lipo wouldn't fit. So it is a side opening hatch.

 

Thanks for the help again guys what would I do without this forum. Oh I know... Crash. heck lets face it I do that anyhow.