Banshee
05-23-2009, 08:06 PM
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Banshee
Hello,
Firstly, I’d like to thank all of you who have contributed to this forum.I’ve done much reading here, and learned a lot.It is very much appreciated.
I’m fairly well along on the Banshee, and have some time now to be able to post some photos, as well as a few specifics regarding any deviations from the plans that I’ve incorporated.This is actually my second Banshee, but the first was built over 30 years ago, and nearly 30 years passed since I’ve pick up the hobby again.My most vivid memory of the first Banshee is aileron flutter……. one of those things that stick with you.
A short kit was obtained from Eureka Aircraft, but the desire to use barn door ailerons (see above) steered me to cutting ribs based on the original design as documented in the Flying Models plans.Ribs were drawn and cut using Profili software.
The original airfoil, at approximatley 13%, is a bit thicker than the J&J plans.
Please feel free to jump in.
Doug
05-23-2009, 08:20 PM
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RE: Banshee
Dave Brown retracts are installed.In an attempt to get a bargain, I purchased an older Airtronics Retract servo.Hey, it was $10!……however.
The servo rotates about 190 degrees, and when used on the DB retracts, will rotate past the point of locking the legs in place.So a Futaba gets the job.Installation of the main gear was fairly straight forward.
Standard Digital JR servos just fit into the wing completely enclosed.
05-23-2009, 09:19 PM
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RE: Banshee
The DB nose wheel retract did require that plywood stand-offs had to be attached to the rear of the firewall. A front bracket on the nose wheel extends past themounting plane, preventing a flush fit to the firewall. I suspect that the bracket is just not bent at asharp enough angle, as a replacement backet that was sent to me exhibited the same issue.
Anotherfall back to theFlyingModels plans was the use of angleddowels for thefront of the wing. Sincethe nosewheelcutout removed the center section of the bulkhead, two dowels seem to be required. With the mid-wing design, I suspect that straight dowels will eventually go oblong with the wing being removed with a downward motion before they can be pulled rearward.
Anotherfall back to theFlyingModels plans was the use of angleddowels for thefront of the wing. Sincethe nosewheelcutout removed the center section of the bulkhead, two dowels seem to be required. With the mid-wing design, I suspect that straight dowels will eventually go oblong with the wing being removed with a downward motion before they can be pulled rearward.
05-24-2009, 08:50 AM
#4
RE: Banshee
Very nice workmanship Doug. What Banshee variations are out there? You mentioned Eureka, FM and other sources? I have the FM plans somewhere in my stash.
Several years ago, Jersey Jim was at an airshow at our local flying strip and put on a demo that rivaled the full size aerobatics. The crowd loved it. IIRC, Jim was using a Proline radio, Rom-Air retracts and a Webra Blackhead .61.
05-24-2009, 09:19 AM
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RE: Banshee
Regarding Banshee variations, from what I understand, the Eureka short kit is a exact replication of the original kit produced by J&J Industries in the early '70s. In comparing the J&J plans to the FM plans, two things jump out at me; 1) a difference in the airfoil, and 2) the length of the fuselage being longer from the leading edge bulkhead to the nose on the J&Jkit. I would speculate that the airfoil was changed on the J&J kit to allow for "standard" strip aileron stock to be used in the kit (the thicker airfoil on the FM plans does not transition into what I found available for aileron stock), and, the longer nose on the J&J kit makes it easier to install the fuel tank and retracts.
Actually, placing retracts and a fuel tank into the FM layout would probably cause me to develope a twitch.
You got to see Jersey Jim put on a demo! Just too cool. I understand that he's capable of being quite the showman.
I still have my ProLine single stick, but it will probably remain on the shelf a bit longer.
Doug
05-24-2009, 09:20 AM
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RE: Banshee
Prior to placing the top sheeting on the wing, both the bottom sheeting and the ribs were scored at the location of the aileron cut-out.With the top sheeting installed, the score marks were simply cut through, and the aileron snapped out.
Also, balsa blocks were installed in the wing for hinge attachment and for producing the concave shape for the military style hinges.All control surfaces are of the concave/convex configuration.
Additional block was installed for the angled wing dowels, and 1/16 shear webbing from the aileron servo inward, anda plywood dihedral brace was also included.
05-24-2009, 10:39 AM
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RE: Banshee
Very nice. I remember Jim Martin at bunches of meets in the early 70's.
I built 2 banshees back then. One from FM plans, one from the J&J kit. Both flew the same. Don't remember if there were any differences.
I built 2 banshees back then. One from FM plans, one from the J&J kit. Both flew the same. Don't remember if there were any differences.
05-24-2009, 04:02 PM
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RE: Banshee
WEDJ, is the photo taken in the field the FM plans?
Finally, I did the majority of the fuselage shaping prior to putting the nose blocks on.This allowed the shape to be drawn on the firewall, and to be referenced during shaping.With the nose blocks on, it can be difficult to know how far into the fuselage has been sanded.A sanding fixture was used to bring the edges to 45 degrees.I found this helpful, as it gave me “something to sand to”, a point of reference, when making the final curve.The fixture shown was used from the firewall to the trailing edge location of the fuselage.
A couple of things on the Fuselage were done differently than indicated on the plans.Firstly, the top sheeting is called out as a piece of 3/8, and shows that the sheeting will require cross-grain saw cuts part way through the wood in order to facilitate bending to the top contour.I recall that this method, although allowing me to make the bend, did not necessarily make life that much easier, and created a lot of voids that filled with glue, making the final shaping that much more difficult.
So….two pieces of 3/16” were used.This thickness made the bend easily, and produced a typical amount of glue for a laminate joint.As a bonus, you get the added strength of a laminate.
In regards to the ¾ thick triangle stock longeron, I found these impossible to sufficiently bend to shape (and remain flat), even after soaking in water for 24 hours.However, these little darlings were ceremoniously split length wise.After cutting in this manner, installation was a nonevent.Of course once the second/top piece of the triangle stock is installed on top of the first, it’s a bit longer than the bottom piece, and doesn’t align perfectly, resulting in a few small gaps.However, these gaps are insignificant compared to the gaps from relieving with a Zona saw.
Finally, I did the majority of the fuselage shaping prior to putting the nose blocks on.This allowed the shape to be drawn on the firewall, and to be referenced during shaping.With the nose blocks on, it can be difficult to know how far into the fuselage has been sanded.A sanding fixture was used to bring the edges to 45 degrees.I found this helpful, as it gave me “something to sand to”, a point of reference, when making the final curve.The fixture shown was used from the firewall to the trailing edge location of the fuselage.
05-30-2009, 03:54 PM
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RE: Banshee
Being a mid-wing, and with the retract servo and linkage mounted on the bottom of the wing, a removable belly pan is nearly a necessity.
In regards to the rearward plate, an alignment plate with two dowels, and a 10-32 nut was mounted on the wing.The surface of the plate was eyeballed as being parallel with the centerline of the wing.This is to allow the belly pan to be removed perpendicular to the zero axis of the plane.If the alignment plate was attached flush to the rearward section of the wing, the pan would have to be removed in a reward direction because the dowels would be angled towards the rear; and that is not possible as the front of the pan would hang-up on the leading edge of the wing.
The pan has to be removable straight upward with this layout.
Both of the rear plates were clamped together and drilled with ¼” holes.Dowels were glued into the bottom plate, along with the nut, and then mounted to the wing.The top plate was then located and screwed on the bottom plate.
Drill the access hole for the 10-32 bolt into the belly pan.
Now it was just a matter of getting a ½” balsa block to fit over the plywood plate, with clearance holes for the dowels, and a slip fit with the sides of the pan.This balsa block is what will attach the plate with the holes onto the pan.Epoxy was applied to the balsa block, placed onto the exposed plate, and the pan aligned.The balsa block can be pressed down onto the plywood through the 10-32 access hole.
The front plate was done similarly.
I hope the pictures help…………
06-05-2009, 04:31 PM
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RE: Banshee
The canopy turned out to be significantly easier than I had anticipated.And although I make every attempt to not use CA adhesive, it made this assembly neat and strong.
Two templates for the canopy can be taken from the plans.The first is a profile former, which will form a “spine” on the center of the fuselage, and, the second template is the top of the canopy.After the former is traced from the plans, two adjustments are needed.The top of the former needs to have ¼” removed from the top, and 1/16” from the front.
The top is made from ¼” stock cut to shape, and its’ sides sanded to an angle such that when the canopy sides are installed, they will have some area that is flush to be glued.The profile former and the top are glued in place.
The canopy front and sides are made from four pieces of 1/16” balsa.The templates for the front section were made by taping paper to the former and top, slowly creasing the paper with a fingernail, and cutting away what doesn’t belong.Note the grain direction of the front pieces on the photos.The two front pieces were joined and the bottom edges feathered prior to gluing in place on the plane.A bit of water was used to encourage bending.
The two sides pieces were cut from templates.If I had do make these pieces again, I would run the grain vertically, rather than horizontally as shown in the photo.There is a slight concavity to the sides, and although it looks cool, it wasn’t what I intended, and will be difficult to finish both sides of the canopy evenly.
A piece of tape marks the line where the sides need to be cut, and the bottom edges of the sides are also feathered.
A judicious amount of filler, and done.
06-05-2009, 04:40 PM
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RE: Banshee
I’ve got a bit of filling and sanding, pushrod installation, and general fussing to do and then she’ll be ready for glassing.The weight of the empty plane prior to finishing will be under 3 ½ pounds, and might just put me on target of under 7 ½ pounds auw.With the flying season in full swing, and some other commitments, I don’t know if there will be air under its’ wings this year or not.
Thanks for checking in.
Doug
12-07-2009, 05:25 PM
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RE: Banshee
With snow on the ground, I guess it’s time to get back at it. Hope that everyone managed to get a few flights in this summer.
The servo’s, pushrods, and control horn bearing surfaces are installed. The control horn bearing surfaces are simply balsa inserts place with the grain parallel with the horn screws. The inserts are then hardened with thin CA.
Elevator and rudder servos are installed, but I’m wondering if a metal gear servo might be best on the rudder/nose wheel. Currently it’s just a standard JR digital. It isn’t so much damage to the gear train that concerns me, as it is having a damaged servo pulling excess current, and not being aware of it. I’ll be flying from a grass field, but it probably rates an 8 out 10 as far as roughness. Thoughts?
The rudder itself is nearly contest grade balsa, which is nice and light, but I thought it best to inlay two pieces of carbon fiber rod. They are epoxyed in place, and attached to the control horn bearing surface.
The servo’s, pushrods, and control horn bearing surfaces are installed. The control horn bearing surfaces are simply balsa inserts place with the grain parallel with the horn screws. The inserts are then hardened with thin CA.
Elevator and rudder servos are installed, but I’m wondering if a metal gear servo might be best on the rudder/nose wheel. Currently it’s just a standard JR digital. It isn’t so much damage to the gear train that concerns me, as it is having a damaged servo pulling excess current, and not being aware of it. I’ll be flying from a grass field, but it probably rates an 8 out 10 as far as roughness. Thoughts?
The rudder itself is nearly contest grade balsa, which is nice and light, but I thought it best to inlay two pieces of carbon fiber rod. They are epoxyed in place, and attached to the control horn bearing surface.
12-08-2009, 10:44 AM
#18
My Feedback: (11)
RE: Banshee
You won't need special servos in any part of the airplane. Remember, the airplane was first flown when servos were rated at about 3-4 inch-pounds of torque, which is 48-64 ounce-inches of torque. Nosegear steering and rudder were almost aways controlled from the same servo. Only five servos were usually found inside those models: one each for ailerons, elevator, rudder/nosegear steering, throttle, and retracts. Some people would add a sixth servo for fine-tuning the needle valve.
You could use four S-148 servos or equivalent and do OK, but a midrange servo , such as the S3102 would be nearly ideal for most vintage Pattern models.
You could use four S-148 servos or equivalent and do OK, but a midrange servo , such as the S3102 would be nearly ideal for most vintage Pattern models.
12-08-2009, 12:17 PM
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RE: Banshee
Only five servos were usually found inside those models
Ray
12-08-2009, 05:38 PM
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RE: Banshee
ORIGINAL: Bax
That's right. Four servos for fixed gear, five servos with retracts (when used).
That's right. Four servos for fixed gear, five servos with retracts (when used).
I see that you have recommended a Metal Gear Servo with the S3102. I'm uncertain what the "weak link" is in a servo that is subject to cyclic shock, as I suspect would be the case with a nose wheel. But I think that the simplest/cheapest/lightest way to mitigate a failure would be to use a Metal Gear Servo. I think I'll get one.
My primary reason for using seperate aileron servos was not for torque purposes, but to allow for programming differential into this bird if need be. Secondarily was the use of shorter pushrods to reduce any potential flex.
Ray,
I wish you'd let me know earlier about the ProLine servos. I could have saved a couple of bucks .............
Doug
12-08-2009, 07:31 PM
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RE: Banshee
Sorry Bax - misread your post.
Doug - I envy you having a ProLine. I always wanted one after fondling Bob Violett's transmitter (pardon [X(]) at the 1972 Pylon W/Cs. Those sticks were works of art. I don't think ProLine were ever distributed in the UK. Even if they had been the cost would probably have been prohibitive although I did briefly use a (second hand) Kraft Gold Medal set.
Ray
Doug - I envy you having a ProLine. I always wanted one after fondling Bob Violett's transmitter (pardon [X(]) at the 1972 Pylon W/Cs. Those sticks were works of art. I don't think ProLine were ever distributed in the UK. Even if they had been the cost would probably have been prohibitive although I did briefly use a (second hand) Kraft Gold Medal set.
Ray
12-09-2009, 11:01 AM
#23
My Feedback: (11)
RE: Banshee
ORIGINAL: DougC1
I see that you have recommended a Metal Gear Servo with the S3102. I'm uncertain what the ''weak link'' is in a servo that is subject to cyclic shock, as I suspect would be the case with a nose wheel. But I think that the simplest/cheapest/lightest way to mitigate a failure would be to use a Metal Gear Servo. I think I'll get one.
I see that you have recommended a Metal Gear Servo with the S3102. I'm uncertain what the ''weak link'' is in a servo that is subject to cyclic shock, as I suspect would be the case with a nose wheel. But I think that the simplest/cheapest/lightest way to mitigate a failure would be to use a Metal Gear Servo. I think I'll get one.
12-09-2009, 11:54 PM
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RE: Banshee
Doug seeing your thread and the pictures sure brings back memories.
Here is my old Banshee from 1974 flying on a Rossi rear rotor 60 and rhom Air retracts. Great flying bird but in the end I fell in love with the Tiger Tail. The Proline radio brought back additional memories as this plane was flown using their open gimble single stick model. In fact I may still have a set of servo gears floating in the recesses of my "stuff".
If you stay with the strip ailerons I would stiffen them with carbon veil to help insure that flutter doesnot start because of torsional weakness.
Here is my old Banshee from 1974 flying on a Rossi rear rotor 60 and rhom Air retracts. Great flying bird but in the end I fell in love with the Tiger Tail. The Proline radio brought back additional memories as this plane was flown using their open gimble single stick model. In fact I may still have a set of servo gears floating in the recesses of my "stuff".
If you stay with the strip ailerons I would stiffen them with carbon veil to help insure that flutter doesnot start because of torsional weakness.
12-10-2009, 03:41 AM
#25
RE: Banshee
So far as rudder/nosewheel steering servos are concerned the nylon gear types are best. The plastic will absorb a lot more shock the a metal gear servo, and standard servos are fine, as Bax and RFJ allude. Use a yellow nyrod inner for the steering bit and any major shock will simply deflect the rod and leave the servo alone. My models (Atlas, Curare, Superstar, Sicroly etc) have only flown off grass and have been doing so for over five years with no servo problems at all. Consider to, that taxiing around the field is not the major part of model flying, and takeoffs and landings are all done with the nosewheel off the ground anyway, so there is little need for much steering, and very little wheel movement (left and right) is actually needed. You have probably seen trike models darting all over the field on takeoff and landing, a sure sign of way too much steering movement. Rudders steer airplanes, not wheels.
Evan, WB #12.
Evan, WB #12.