Seagull Hurricane Laser

[Jon H]

Wing section choice in artf's often confuses me. I bought a 40 size seagull PT19 as i wanted something slow and floaty. Snag was, it had a wing like a razor blade and went like a missile.

In the case of the hurricane, its already got a thick wing so why change it? Certainly i dont see why you would make it thicker. Most odd.

The worst of all though has to be the black horse he111. A friend has one and it simply has no section at all. Its just a thin triangle with a slightly rounded front edge. Unsurprisingly, the model is like a manhole cover in the air.

In any event, what i think i might do next time we fly one of these is to gain some altitude, drop the gear and flaps then adjust the elevator flap mix on the fly to see if we can get to a nose up '3 point' angle. We can then adjust the rates, again on the fly to make sure we have adequate control. Obviously this is not a one man job, but it should be quite interesting.

[SR 71]

Yes, dont forget to video it Jon

[Nigel R]

"Obviously this is not a one man job, but it should be quite interesting."

Not a bad plan.

I'd be surprised if you couldn't assign a dial to a mix somehow to achieve what you want.

[Tim Flyer]

I must admit even as a layperson and certainly no-expert on wing sections, the Seagull “interpretation” of a Hurricane wing surprised me . It seems way too thick especially for the fairly modest chord. I’m also surprised that they released it with such difficult flying characteristics. If it’s challenging an expert like Jon I think they have got their market wrong. Other scale Seagull models I have flown have been much better sorted.

[Jon H]

Posted by Nigel R on 13/02/2020 13:31:35:

"Obviously this is not a one man job, but it should be quite interesting."

Not a bad plan.

I'd be surprised if you couldn't assign a dial to a mix somehow to achieve what you want.

Its more likely i will fly and have someone else press buttons. This is how Tim and i first dialed in the elevator/flap mix on his Hurricane.

[Jon H]

Posted by SR 71 on 13/02/2020 12:24:20:

Yes, dont forget to video it Jon

I will use my 5th arm to hold the camera dont you worry

[Chris Walby]

I have been called many things, but not that before. I'll try and focus on the hurricane, but the last 15ft is the most lively.

My money is on making heavier, its just a case of how much more lead will it need.

Someone mentioned that Seagull mostly use the same 33cc engine for there various models, so on that basis I wonder what their AUW weight is when they did all their testing?

Perhaps if they were up in the 20lb area they didn't have a problem?

[Piers Bowlan]

Posted by Nigel R on 12/02/2020 15:57:34:

I suspect the lack of reflex might be the straw, here.

I know that pitching moment of the wing is quite a large determinant when figuring out the size of a tailplane.

I am however, only an armchair amateur.

 

I agree Nigel, the thick wing section gives the section a large pitching moment which is pretty constant with respect to angle of attack. However at high angles of attack the centre of lift moves forward towards the centre of gravity reducing the downforce required by the tailplane/elevator and consequently reducing pitch (longitudinal) stability. This makes the elevator over sensitive at high angles of attack/low airspeed. As others have suggested (Jesus, Nigel) moving the c of g forward (to 25%) should improve low speed pitch stability (or fit a thinner section wing - not scale ).

As we have probably all experienced, it is not uncommon for ARTF instructions to be incorrect regarding c of g position .

Regarding increasing the all up weight Chris, I don't think that will make any difference - unless the weight is added to the nose. A higher wing loading will only exacerbate the problem but I may be wrong. Heavy aeroplanes don't fly better in my experience, except for riding turbulent air. 

Hope you get it sorted soon.

Edited By Piers Bowlan on 13/02/2020 15:13:43

[Jon H]

I am quite happy with the c/g i have to confess. The model will fly at a cruise speed with a very slight down trim and this is exactly what i would expect from a warbird. It also feels right when you pick it up and there is no tail sag when flying along. Barrel rolls are sweet as well and it feels great in the air as long as you keep the speed above that critical point. If it were tail heavy i would expect it to drop its tail more as the speed came off but we have the opposite problem.

We need to bring on some nice weather so we can have at this again. if we were real clever we could set up two cameras. One watching the model and one watching the sticks.

[Piers Bowlan]

I appreciate that the model flies well in normal flight Jon, so from that perspective the c of g is in the 'right place' for that regime of flight. However if the model is uncontrollable at landing speeds then you have a problem which I feel no amount of elevator /flap mix tweaking will sort out. I will be pleased if I am proved wrong as that would be a simple fix. However, even if moving the c of g forward had a slightly detrimental effect on cruising flight and the models aerobatic repertoire, it might be worth it if the landings are survivable (and look more realistic too). C of G position can be a compromise like so many things in aircraft design. I wonder how many Seagull Hurricanes have been written off or sustained serious damage following one of these roller coaster landings?

A larger tailplane or a different wing section would no doubt transform the model but those are not options so you just have to change what you can (C of G). Such a shame, as it it is such an impressive looking model.

Incidentally I think this article covers the aerodynamic problems you are encountering.

Edited By Piers Bowlan on 14/02/2020 08:53:33

[Chris Freeman 3]

Do you have any expo on the elevator? Years ago whilst teaching my son to fly a Spitfire I set up some expo to soften the elevator and that it made the Spitfire a pig to land as it would not settle on the approach and porpoise. We found that flaps and undercart down would lower the nose so you counter with some up and when you want to land the expo is now working against you as it is now a super sensitve elevator. Taking the EXPO out changed the situation and the Spitfire was back to the pleasent landing one that I was used to.

[Jon H]

Posted by Piers Bowlan on 14/02/2020 08:47:09:

I appreciate that the model flies well in normal flight Jon, so from that perspective the c of g is in the 'right place' for that regime of flight. However if the model is uncontrollable at landing speeds then you have a problem which I feel no amount of elevator /flap mix tweaking will sort out.

Edited By Piers Bowlan on 14/02/2020 08:53:33

With gear and flaps down its almost impossible to hold the nose up without the ele/flap mix so adding more weight to the front wont help us and the rollercoaster nature of the approach seems to stem from the fact that the wing just provides so much lift that a small deviation in pitch, in either direction, has a significant impact. As the model is very slow when landing the tail looses effectiveness, which is not uncommon on a warbird, so higher rates are needed. This would all be fine if the wing was not so sensitive to pitch at low speed and that where we will focus our attention. 

Chris, no expo. Expo is a powerful tool but it is over used and very often used at the wrong times. I had a similar experience to you with a H9 Spitfire where a club mate could not get the thing on the ground as it was all over the place on approach. I looked at his tx settings and was horrified to find 60% rates and 65% expo. I dropped the rates to 25% and ditched all the expo. It was on rails after that.

The trap was he set the radio up according to the deflections called for in the manual. As it was too sensitive he added expo, as thats what popular misconception told him to do. This didnt help so he added more, and more... When i and another warbird proficient friend looked at it we immediately saw that the travel was too high and that was the root cause of the problem. Out of 12 models only one of mine has 10% expo in it and even then only on 1 channel. Its just not needed on the rest of them.

Always get rates set first, then add expo as the cherry on top. On warbirds starting with 30% is just insanity in my view as you are on the back foot before you even begin.

 

Edited By Jon - Laser Engines on 14/02/2020 09:39:58

[ARC]

Picking one of these up tomorrow , either running on my saito FG30B or my FG40. My previous blackhorse hurri flew lovely but did angle the oleos forward by about 3-4mm which helped alot on the nose over issue.

[Chris Walby]

All the best ARC and please keep us informed as to how you get with the build and flying. Any questions please post as we all want to help if we can,

[Tim Flyer]

Just thought I might update the thread with pictures after Jon flew my repaired Hurricane on Friday . It had become a “hangar queen” after I had repaired it after a belly crash onto the crop field last year . As it had had extensive repairs I wanted Jon to test it and set it up. It still seems a “mean machine” and is intolerant of errors, yet it looks very nice in the air . We also did a video of the very considerable stick input required to successfully land it.
Here are the pictures

[Jon H]

Looks nice in the photos!

Its been a real mixed bag with SG Hurricanes lately.

Last weekend Chris brought his model out to play with a view to finding out what on earth is going on. More weight was added on the c/g to try and combat the ballooning we were seeing on landing when trying to flare.

Takeoff was uneventful and the model was trimmed. It flew...ok, but was really pitch sensitive and generally a bit of a handful. I then lowered the gear, flaps, and was just turning into my base turn when the model just fell out of the sky. I had applied a little right aileron to just roll into the turn, the model responded as expected, and once the bank angle was as i wanted i moved the ailerons to about 10% left just to hold the attitude. Imagine my horror as it continued to roll right ending up in a vertical dive.

Initially i thought the radio had gone as i had no control at all. The telemetry system seems to rule that out however as no signal loss was recorded.

checking the remains revealed that one aileron servo horn was missing its retaining screw (found later inside the wing) so its possible the horn came off in flight or slipped a spline which would have made things interesting.

Did i stall/spin it? I dont know. If i did it is the first model i have ever stall/spun on approach to land. I cant see how it spun either as i had no up elevator pressure (in fact a little down), some power, and the nose was below the horizon. Did i get myself disorientated and roll the wrong way? maybe? Many years ago i did that with a galaxy mustang but the situation was very different as i took my eyes off it and i was crossing the low sun. This time i didnt have either of those issues, and everything was going exactly as i expected up until the roll over. I even simulated the approach again with my smaller 62 inch Hurricane that i had up there that day. Flown at such a distance that it appeared the same size and with the same camouflage pattern it was clear which way everything was pointing so i cant see how i could have messed it up.

Ultimately, i dont know what happened and that is the worst part.

Fast forward a week and Tim wanted me to have a go at breaking flying his as it either needed to earn its keep or go in the bin. Off we went again and for some reason this example flew better after being broken in half. It was better than i remember and more pitch stable than Chris's example the week before. Swooping around was quite nice but there were still these random pitch changes going on and it was hard work keeping the thing straight. Loops were a nightmare and rolls were weird as the model would climb while inverted if left unchecked. I think the incidence on the thing is just a total dogs dinner and Tims example has been improved a bit by getting snapped in half.

So, with great trepidation it was time to land and after quite some wrestling, i got the model down nicely. I breathed a heavy sigh of relief and muttered something derogatory about the model. This was met with some confusion as the landing looked lovely from the outside. I then did another lap of the field so the guys watching could focus on the tx this time and not the model. The result of this was more profanity as it came as quite a surprise just how much input was needed to get the blasted thing down without it ballooning away in the flare.

We do have a video, i will try and get it uploaded, and now i know how to get it down its fine and quite enjoyable, but long story short this thing is really not easy to fly and i wont be recommending it to anyone.

[Tim Flyer]

Thanks for posting this Jon. I was hoping you would give the pilots view .
As an observer the plane looked really great in the air, but when we looked at what you were having to do on the sticks to keep it stable, it was crazy. The stick movements needed for a landing are unbelievable!
I think Seagull need to redesign this model.
Seagull do make some really good flying planes such as their P47 which I own, I’m afraid I think this one is very badly flawed,

It seems quite revealing that there are no other reports of regular flying of this particular Hurricane .
This is quite surprising given how popular Hurricanes are. My guess is that most do not make it past their maiden flight.

 

Edited By Tim Flyer on 07/09/2020 22:15:54

[Tim Flyer]

Here is a link to a video we took of Jon landing the Hurricane again shortly after the above shots. The wind was a good WSW at about 14 mph with a slight cross wind down the runway which runs E to W.
The video was taken to show the quite large stick inputs needed rather than just viewing the plane.
**LINK**

Edited By Tim Flyer on 11/09/2020 10:52:00

[Ron Gray]

Very interesting especially very little rudder input and quite a bit of right aileron.

Edited By Ron Gray on 11/09/2020 11:15:40

[Jon H]

In order to make life easy i landed a little diagonal to reduce the cross wind component. That is why i nearly fell off the runway the first time. I didnt want to use the rudder too much as it causes a large nose down pitch at high deflection.

As for the ailerons, they were busy keeping the wings level but its the elevator that is hard work.

[Michael Kulagin]

Didn't want to start a new thread but there is an interesting article, for once, in today's Mail Online. It's titled 'bravery in the eye of a Hurricane' and written by Jane Fryer. It's about the Hurricane in the Battle of Britain and she takes a flight in a two seater Hurricane operated by Flyaspitfire based at Biggin Hill. There is a short clip of the Hurricane in action.

[neil martin 1]

Looks like someone has got it nailed.....landings look good.

COG is 110mm and he's taken half an inch off of the length of the gear

https://youtu.be/0KoTlzU27-8

[dave parnham]

He does mention a good Gyro system is a must in the comments

[Jon H]

Long time since an update but a plan is afoot. 

 

Following the very successful maiden flight of my DB Hurricane Tim and i were discussing his seagull version. Clearly the Hurricane itself is not the problem, just something in the SG design. 

 

So, we are going to check out all the incidences as discussed before. If they look wrong, we will adjust them and see how things end up. IF they look ok, or the adjustments fail to provide a satisfactory result, there is an idea about scaling down the 88 inch DB wing and fitting it to the SG model. The problem just be in the wing as a fuselage is difficult to screw up. I mean, engine at the front, tail at the back, cockpit in the middle. Its not difficult. 

 

Anyway we were musing about this idea of a new wing and it might give an interesting result. Its possible we could get away with only changing the outer wing panels as that would be dead easy.