DerJet Hunter here!
05-11-2013, 10:43 AM
#27
Thread Starter
RE: DerJet Hunter here!
Big G
Yes, amazing company. Each time we discus improvements they respond immediately, since my kit a few things have been changed, its more important to them that things are as good as possible, rather than pumping out kits.
D
Yes, amazing company. Each time we discus improvements they respond immediately, since my kit a few things have been changed, its more important to them that things are as good as possible, rather than pumping out kits.
D
05-11-2013, 11:57 AM
#28
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RE: DerJet Hunter here!
Geoff /Dave ...now that would inspire me to buy a Derjet model,,a company who listen ! And aren't afraid to discuss issues no matter how small !
09-21-2013, 07:46 AM
#30
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Barry, Sorry to send the construction manual so late. The manual comes into the final soon. You may start at 29 cm of the CG point.
Regards, Jack, DerJet Model
Regards, Jack, DerJet Model
10-07-2013, 03:33 PM
#32
Any news on this plane ? Need to buy a plane of this size and I love the Hunter...... but also the Vampire. Derjet has both models but trying to make a decision on which way to go.
10-07-2013, 05:39 PM
#33
Here are some pictures taken by Ken Simmons at Sepulveda basin. Kim McNulty did a great job putting it together, including his first attempt of weathering. We maidened it at 28cm from trailing edge but was grossly tail heavy, ended up 5 more oz of lead up in the nose. A total of 3 flights on the first day, also to note, the gears didn't want to come up until you roll it inverted and give it negative G, when they did, somehow didn't want to come down, so had a gear up landing on the last flight, some damage, but will fly again, hopefully sooner than later...
I must add, once the gears retracted, it was just a pure joy to fly
Cheers,
Barry
02-26-2014, 10:00 PM
#35
I put the first two flights on the Hunter today. I had a very hard time getting the jet to rotate. The nose sits very low. Like Barry, I was unable to get the mains to retract in the air. The nose gear and door worked fine. The Hunter landings were very nice. It had very good power with the 120sx.
02-26-2014, 11:43 PM
#36
Thread Starter
On the ground what psi do you need to retract the main gear? My guess is that you must have had some good ground speed if you were struggling with rotation (how much flap were you using?) Were you climbing when you first hit the retract switch? The big heavy wheels and draggy gear doors mean there is the weight/G increase to the cylinders if you were climbing and aerodynamic drag if it was travelling fast.
On my Vampire I rotate, check the climb go level a second or two-while hitting the gear switch and the gear always goes.
Looks great in that scheme!
Dave
On my Vampire I rotate, check the climb go level a second or two-while hitting the gear switch and the gear always goes.
Looks great in that scheme!
Dave
02-27-2014, 12:03 AM
#37
Nice, but a shame they got the wing leading edge so wrong!
The leading edge extension was fitted to the F 6 wing to prevent pitch up near the stall. The le extension projects well forward (about 4 inches) of the original le RIGHT to the tip, it does NOT taper to the original le.as on this model.
Mick Reeves got this right, the forthcoming Tomahawk Hunter has it right, DJ and Airworld, wrong.
Doing it it right would improve scale accuracy and improve handling near the stall, reducing the possibility of tip stall when pulling G.
Take a look at the real Hunter, F 6 onwards, although the Danes modified their F4s to improve handling and when RAF F4s were converted to T7s the le extensions were also added.
David.
The leading edge extension was fitted to the F 6 wing to prevent pitch up near the stall. The le extension projects well forward (about 4 inches) of the original le RIGHT to the tip, it does NOT taper to the original le.as on this model.
Mick Reeves got this right, the forthcoming Tomahawk Hunter has it right, DJ and Airworld, wrong.
Doing it it right would improve scale accuracy and improve handling near the stall, reducing the possibility of tip stall when pulling G.
Take a look at the real Hunter, F 6 onwards, although the Danes modified their F4s to improve handling and when RAF F4s were converted to T7s the le extensions were also added.
David.
02-27-2014, 02:58 AM
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http://www.flickr.com/photos/photonu...n/photostream/
It looks from the full-size that David G is right here. I have looked at photos of a few full size planes that have been caught almost plan view. A straight edge on the outer wing leading edge shows it to be parallel. The 3 View must be wrongly drawn! There is a Hunter at Flixton, my local air museum, I might pop in and check it.
John
It looks from the full-size that David G is right here. I have looked at photos of a few full size planes that have been caught almost plan view. A straight edge on the outer wing leading edge shows it to be parallel. The 3 View must be wrongly drawn! There is a Hunter at Flixton, my local air museum, I might pop in and check it.
John
02-27-2014, 04:44 AM
#42
I knew my post would be controversial because most of the Hunter drawings are wrong on this point. Most, but not all, of publications I have seen, seem to copy the mistake.
However the LE extension play an important aerodynamic function as they change the mean camber liner at the outboard wing section, increasing the max CL and reducing the angle of incidence (the chord line of the extension is angled downwards, to prevent tip stalling which results in pitch up due to forward movement of the C of P, on a swept wing such as the Hunter. The Phantom and HP Victor also have, had, extended drooped outboard LEs. and there are probably many others too.
My point is that the Hunter models from DJ and AirWorld, by getting the leading edge wrong, are degrading the model's aerodynamics. Doing it correctly would reduce the chance of tip stall, making the machine safer to fly and, of course, more accurate, scale wise. !
I know the Reynolds numbers of the model are totally different to the fullsize machine but every little helps.
But don't take my word for it, go and look at a real Hunter !! I will await John's Flixton visit report !
David.
.
However the LE extension play an important aerodynamic function as they change the mean camber liner at the outboard wing section, increasing the max CL and reducing the angle of incidence (the chord line of the extension is angled downwards, to prevent tip stalling which results in pitch up due to forward movement of the C of P, on a swept wing such as the Hunter. The Phantom and HP Victor also have, had, extended drooped outboard LEs. and there are probably many others too.
My point is that the Hunter models from DJ and AirWorld, by getting the leading edge wrong, are degrading the model's aerodynamics. Doing it correctly would reduce the chance of tip stall, making the machine safer to fly and, of course, more accurate, scale wise. !
I know the Reynolds numbers of the model are totally different to the fullsize machine but every little helps.
But don't take my word for it, go and look at a real Hunter !! I will await John's Flixton visit report !
David.
.
02-27-2014, 07:08 AM
#44
Thread Starter
David
Obviously you are correct on the scale outline, flying wise I've flown a lot of Hunters and all are easy going and not at all tip-stally. The fact the MR Hunter is one of the scale ones proves the point, as the two or three I have flown were the worst handling Hunters I have flown!
Its a pity molded aeroplanes are often done wrong, most of AW's models are wrong in one way or another, but they all look and fly great as models, so I guess it depends what is important to you.
Dw
Obviously you are correct on the scale outline, flying wise I've flown a lot of Hunters and all are easy going and not at all tip-stally. The fact the MR Hunter is one of the scale ones proves the point, as the two or three I have flown were the worst handling Hunters I have flown!
Its a pity molded aeroplanes are often done wrong, most of AW's models are wrong in one way or another, but they all look and fly great as models, so I guess it depends what is important to you.
Dw
02-27-2014, 08:09 AM
#45
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I have been to the museum and taken some photos which are exactly as expected. The photos are the same as Jack has posted except the Singapore Hunter is nice and clean and free of algae! I took a photo at the junction of the extension on the inside. There is no droop down just a smooth shallow curve from the underneath upwards to the leading edge.
This is a list of the planes in the museum, nice to have it close.
http://www.aviationmuseumguide.co.uk/museum_flixton.php
John
This is a list of the planes in the museum, nice to have it close.
http://www.aviationmuseumguide.co.uk/museum_flixton.php
John
Last edited by Jgwright; 02-27-2014 at 08:12 AM.
02-27-2014, 08:29 AM
#46
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Dave Wilshire, since you had both the Ripmax and the Der Jet Hunters, how did the Ripmax L.E. extension look? I would assume since it is basically the Mick Reeves Hunter that the Ripmax would be correct....
02-27-2014, 09:02 AM
#47
Thread Starter
No Ripmax ones are like the DJ and taper to the tip. Although its based on the MR model, the Ripmax model is very different right from undercarriage positioning to incidences, the Ripmax versions I have flown (4) all fly better than the MR examples.
I expect my DJ model to fly well too.
Dave
DJ on a Ripmax wing
I expect my DJ model to fly well too.
Dave
DJ on a Ripmax wing
Last edited by Dave Wilshere; 02-27-2014 at 09:10 AM.
02-27-2014, 10:15 AM
#48
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I put the first two flights on the Hunter today. I had a very hard time getting the jet to rotate. The nose sits very low. Like Barry, I was unable to get the mains to retract in the air. The nose gear and door worked fine. The Hunter landings were very nice. It had very good power with the 120sx.
Kirk
,
Last edited by k_sonn; 02-27-2014 at 10:17 AM.
02-28-2014, 06:02 AM
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Hi all, very interesting theme.
Some months ago I purchased from MR plans, canopy and a set of wing airfoils. I am working on my own CAD plans and the extensión L.E. taper 1°20'34", i.e. is not paralel with the L.E. of the central wing.
BTW is very dificult to get with accuracy the anhedral form the plans, I guess is 3° total anhedral but I'm not sure, any one can help me?
I attach some pics of my electrical nose gear.
B.R.
Jesús A. Serrano
Some months ago I purchased from MR plans, canopy and a set of wing airfoils. I am working on my own CAD plans and the extensión L.E. taper 1°20'34", i.e. is not paralel with the L.E. of the central wing.
BTW is very dificult to get with accuracy the anhedral form the plans, I guess is 3° total anhedral but I'm not sure, any one can help me?
I attach some pics of my electrical nose gear.
B.R.
Jesús A. Serrano
02-28-2014, 01:03 PM
#50
The anhedral angle on the fullsize drawings I have is 2 degrees.
No, the LE extension will not have a LE parallel to the inboard mainplane section. The chord of the extension at the inboard point is just on 6 inches (measured at right angles to the wing LE) and at the tip the chord is just about 4 inches, so the 1 degree difference you noted is about right ! They are just under 10 feet long so they create, in total, an extra 9 sq. ft of wing area and move the normal C of P forward.
For the most part the extension will have NO effect on handling although it will improve the Max CL BUT at the stall (both 1 g and accelerated) it should make things more docile. Remember, in military fighters and trainers the aircraft is often flown very near the stall, i.e in a max performance turn pulling lots of G, is often nibbling at the pre-stall buffet, the point at which the maximum rate of turn is achieved.
Sometimes these small aerodynamic features can have a considerable benefit. The BVM T33 was a dog at the stall, spinning at the drop of a hat. This was caused by the drooped LE at the root, creating undercamber. Fill in the undercamber and it flew much better at low speeds and the instant spin tendencies disappeared.
David.
No, the LE extension will not have a LE parallel to the inboard mainplane section. The chord of the extension at the inboard point is just on 6 inches (measured at right angles to the wing LE) and at the tip the chord is just about 4 inches, so the 1 degree difference you noted is about right ! They are just under 10 feet long so they create, in total, an extra 9 sq. ft of wing area and move the normal C of P forward.
For the most part the extension will have NO effect on handling although it will improve the Max CL BUT at the stall (both 1 g and accelerated) it should make things more docile. Remember, in military fighters and trainers the aircraft is often flown very near the stall, i.e in a max performance turn pulling lots of G, is often nibbling at the pre-stall buffet, the point at which the maximum rate of turn is achieved.
Sometimes these small aerodynamic features can have a considerable benefit. The BVM T33 was a dog at the stall, spinning at the drop of a hat. This was caused by the drooped LE at the root, creating undercamber. Fill in the undercamber and it flew much better at low speeds and the instant spin tendencies disappeared.
David.