Flight Deck

February 2009

.15 Profile Carrier

By Eric Conley

Next to AMA Profile Carrier this is my second choice for a great carrier event. Many modelers that would like to try carrier flying for the first time think this is a good place to start. NOT. The only reason they think this is a good place to start is that they have never flown carrier before. Not that this class has no merit to begin your carrier flying.

The .15 planes are smaller than the AMA Profile planes and for me and the way I build this makes them much easier to manage on my building table. Some flyers use foam core wings made popular by the "Sniper" plane by Bill Bischoff. I have never used foam wings in my .15s because they tend to get mushy over the long run and damage easily in flying accidents. If the foam wings are sheeted with balsa they are much stronger and hold up better but the weight penalty can affect the planes overall performance. It all depends on where you want to put your weight.

I use built up wings made with 1/8 by 3/8 spruce spars, 3/32 balsa ribs, 1/2" by 1/2" balsa leading edge, 1/16 balsa C cap sheeting from leading edge to spar, and a 1/16 by 2 inch balsa D cap sheeting at the trailing edge. This might sound a little complicated but for me it is the way I have built planes all my life and it makes for a very strong but light wing. I have also used 1/2" inch balsa for a wing for .15 carrier and it turned out quite strong but there was the weight penalty and with a marginal airfoil some handling problems in the high speed portion of the flight.

The fuselage is made with 3/8 by 3/8 maple engine mount on top and a 3/8 by 1/2 inch engine mount on the bottom. The lower engine mount is also used to mount the landing gear. The engine mounts are run from the nose of the plane back past the spar location on the wing for maximum strength and then caped with 3/32 plywood from the nose of the plane to a point behind where the engine mounts stop in the fuselage. The fuselage is then caped top and bottom with 1/8 by 3/8 spruce stringers to prevent the fuselage from breaking between the wing and tail assembly when the plane ground loops on a bad landing or trips in deep grass.

The tail assembly is made from 1/8 inch thick medium balsa re-enforced with 1/8 by 1/4 inch spruce spar at the hinge point on the stabilizer. Most of the time I will put a 1/8 by 3/8 inch piece of maple in the rudder that runs down from the top of the rudder into the fuselage, through the stabilizer and down to the bottom or near the bottom of the fuselage. It turns out to be the roll bar for the rudder as well as a good reinforcement for the stabilizer. These small planes are prone to bouncing around and turning over more often than the full size AMA profiles.

In the last couple of years someone came up with the idea of putting 9 to 11 degrees of out thrust in the engine to help the plane stay out at the end of the lines while flying the low speed portion of the event. This has worked out quite well with no noticeable loss of high speed and a lot more control during the low speed portion of the event.

The .15 carrier event has a high speed limit of 70 mph in the high speed portion of the flight. The predominant engine is the Cox Conquest/ K&B Conquest/ RJL Conquest engines that are no longer in production. There are many of these engines out in the field that were used by combat fliers, free flight flyers and RC flyers of yesterday and can be purchased at a reasonable price. OS has made some pretty good .15 engines in the past although at this time they seem to have only one (.15CV-A ABN) which might work. Norvell had a pretty good .15 engine if you can find one of them for sale used. I use a MVVS .15 that has a reverse crank in it. The MVVS is still available although I'm not sure you can get them with the reverse crank at this time. Now if you are really motivated there are quite a few .15 engines from Russia that are used in FAI combat and speed events that could be converted for carrier use. Be prepared to pay a rather high price for the Russian engines unless you can find a used one and then it won't be cheap.

I use the J Roberts 3 line control system sold by Brodak to control my planes and have found them to be quite satisfactory. I advise new modelers to the 3 line systems to use only Brodak equipment, as they are a matched control handle to a matched 3-line bell crank. Many times when you buy mismatched handles and bellcranks you get limited throttle control and this can be a big problem.

Another nice feature of the .15 class is that it is not an AMA event and the rules are more flexible. Bill Bischoff's "Sniper" is a purpose built plane in that it was made to be simple to build and yet give top performance in its carrier class. My first .15 was a Sniper and performed well but following a broken prop and a plane that had disintegrated I chose to build a plane that looked more like a real plane (Bf 109T) using the same movements that the Sniper has. Two planes come to mind that build well for .15, they are the 109T and the British Seafire. Planes that wont build well are the Wildcat and possibly the Hellcat depending on how the Hellcat is made.

The reason that the 109T and Seafire build so well for carrier is that they have inline engines and therefore have a small profile from the wing trailing edge to their nose. This is very important in carrier flying because when you are in the slow flight portion of the event and the wind is coming across the circle it doesn't blow the nose in but does blow the tail in keeping the nose pointed out of the circle for more line tension. The Wildcat and Hellcat have very large nose sections and can be blown into the circle quite easily during the low speed portion of the flight.

Another quirk of my .15 carrier planes that I learned the hard way is that they don't have the power that a good AMA profile plane has. After many missed takeoffs (touching the ground right after takeoff) I lengthened the landing gear legs on my .15s by about an inch and a half. By increasing the angle of attack on the deck my planes now seem to be getting off the deck much better. If you use full up elevator during the takeoff run you actually slow the plane down (a big elevator in the full up position) and as you pass over the bow of the deck the tail goes down and touches the ground before the plane has gained any altitude then with the higher angle of attack the plane skyrockets up into the air and you end up with a missed attempt. The longer landing gear equals better angle of attack on the deck, quicker take off, and fewer damaged props.

So the .15 carrier plane is not complicated (only moving parts are the elevator, throttle and maybe the arresting hook), is easy to build, rugged, easy to repair if damaged, and not fast enough to get you in trouble during the high speed portion of the flight. For the new carrier flier they are a little bouncy and sometimes unpredictable in the low speed portion of the flight due to their low weight. If you can fly a .15 carrier plane successfully you can fly any carrier plane.

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This page was upated Feb. 11, 2009