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Old 10th Feb 2014, 01:36
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JammedStab
 
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I have also flown the Fleet Finch. It is not known well outside of North America so I did not mention it initially. But, it is a good direct comparison with the Tiger Moth. These aircraft flew side by side in Canada with the DH.82C. I believe Portugal had Finches as well.

These two types were in direct competition with each other for purchases by other countries. The Tiger seemed to mostly win out.

For generally similar looking aircraft, they are actually quite different(Fleet 16 vs, DH.82C). Once again, the inflight handling of the Finch is much more responsive than the Tiger Moth. But then again, that goal is not difficult to achieve. While I have not spun either of them, the Tiger Moth did encounter some spin difficulties. It is a contentious subject among Tiger Moth "experts" with many theories and explanations. The bottom line is that the Canadian-built 82C was never modified like so many A models and does quite well without the ugly anti-spin strakes.

Both aircraft are limited in range but the Tiger does have the advantage of certification of an aux fuel tank in front of the pilot to extend range by more than an hour from original. I would give the Finch which lacks external cables for the rudder at least 5 knots cruise advantage over the Tiger Moth. The small vent on the aft side if the Finch fuel tank(at the upper wing trailing edge) seems less likely to result in water contamination than the vent on top of the Tiger Moth tank, which on the A model seems to only have protection by a ball bearing internal design that stops water from going in and then slides up to keep fuel from going out during certain flight maneuvers.

The Tiger Moth can be more vulnerable to water contamination incidents because when in the three point attitude, the fuel sump is not at the lowest point in the tank. Therefore, this and the longitudinal corrugations in the fuel tank can hide water which can reveal itself in flight. Rocking wings prior to or having your colleagues raise the tail to level while sampling fuel could help if you have any reason to be suspicious(or just draining it). Meanwhile the Finch tank was designed with three outlets although sometimes only two are used.

For colder climes, the canopied Tiger wins out as most Finch canopies have long disappeared, possibly because they went to warmer areas such as Mexico after the war. However, both do have heating capability, although mods might be required on your Finch to get it back to original.

Like the Tiger Moth, the Finch does not have much payload capability but the baggage carrying space is definitely larger on the DH.82C.

To be honest with you, I find that the Tiger Moth, for a simple aircraft has a very large amount of things that should be checked on a thorough walkaround including the fairly complex mechanisms under the cowl.

Engine operation is significantly different between the two of them with the Kinner radial engine on the Finch and all the unique aspects of the radial engine operation from longer warm-up to hydraulic lock considerations (although the Gipsy is more vulnerable to a fuel hydraulic lock if the intake manifold drain is plugged). That being said, having the starter on the Kinner makes things much easier along with normal priming instead of the quaint Gipsy Major engine method of tickling the carby(But having to grease the Kinner rockers every few hours, does add to maintenance requirements and it really should be done properly).

I am not sure if Finches came out of the factory with a starter. There are some Tiger Moths modified with a starter. However, when if it comes to a hand-propping comparison, I much prefer the Tiger as it is less force required and the prop is closer to the ground.

The Tigers Gipsy Major engine has been known to have mag difficulties with the old BTH model, sometimes requiring a reasonable tap on the mag to free up the impulse coupling, if you don't hear it click while pulling the prop through prior to start. That along with saving weight and other difficulties has lead to a Slick mag conversion. The Tiger moth has two sets of mag switches located on the outer fuselage wired in series. One for student and one for instructor. Nowadays the front set could easily be accidentally turned off by a front seat passenger. An original Finch has a simple heavy duty rod that moves forward for mags on and aft for mags off. Checking the mags is annoying as there are separate switches located at the most inconvenient spot on the right sidewall between from and rear seats. Remember to keep holding the brakes as you twist around to reach them.

While the DH.82C has trim tabs for elevator trim(unlike the A model) and a nice handle on the right side of the cockpit to operate it smoothly, the Finch trim adjusts the whole stabilizer. An unusual cable system is used on the left side of the pilot for trimming but no location indicated for a takeoff setting. Presetting marks on the cable(although it could slip) or at the fuselage to stabilizer location can be beneficial.

These two aircraft handle completely different not only in the air but on the ground. The DH.82C has a free castoring tailwheel while the Finch has cables directly attached from rudders to the tailwheel unit(internally routed of course).

For the Tiger Moth taxiing, this means much more effort. While differential braking is installed, taxiing requires extra talent due to the brakes being operated by a handle which in combination with amount of rudder pedal deflection dictates the amount of differential. For improved ground handling, brakes can be set up with a slight amount of individual brake application with full rudder deflection. I have had to do a 360 degree turn on the runway while taxiing with a poor brake setup to do what I wanted. I have also seen a Tiger Moth unable to turn toward the desired direction due to relatively strong winds. Fortunately the Canadian version has a hand hold at the end of each lower wing for ground assistance which saved the day in that case.

Meanwhile the Finch with its direct cable linkage to tailwheel unit has as immediate a response to steering that I have ever seen using just the rudder pedals no pre-planning required for effect. There are heel brakes which are reasonably easy to use. Tight turns in the Finch may be difficult depending perhaps on tailwheel modifications.

Many Finches have been modified to have the pilot fly from the back seat. This can reduce the noseover tendency by moving the CG aft. Some but not all of them do have grabby brakes. The CG can be further forward than original due to many having been modified from 125 to 160 hp(although some early models were built with with the larger engine until the PT-22 created a shortage). One aircraft did flip over recently while just taxiing at a high speed followed by brake application and there have been quite a few noseovers. Because of the front pilot seat design, the fuel guage for the Finch is on the bottom of the fuel tank instead of on top for the aft seated pilot in the Tiger.

Takeoff in these two aircraft are very different in terms of control response. For those flying back and forth between the two, a review of techniques is a good idea for each one. With the Tigers Gipsy driven prop(either metal or wood are used) spins in opposite direction to the Finches Kinner driven prop. Opposite rudder inputs for turning moments are required.

Sensitivity to rudder input between the two are completely opposite. The Tiger pilot is used to coarse inputs to get response at lower speeds as its small rudder has lesser effect. Meanwhile, the Finchs large rudder makes it very, very sensitive to rudder input. I try to remind myself to make mini rudder inputs for control for takeoff and landing. I imagine it to be more like a Pitts(although I have not flown one).

For the landing, once again there are differences. The Tiger requires a light touch for the flare to avoid ballooning while the Finch stick requires noticeably more force to be brought fully aft for proper full stall landing. Both aircraft are quite docile on grass. Once again, coarse rudder inputs can be quite normal on the rollout int the Tiger but should be avoided in the Finch.

Where they both provide potential challenge is on pavement but in different ways. The Tigers lesser rudder responsiveness and free castoring tailwheel make it much more vulnerable to crosswinds. Brakes are available but using a handbrake is not necessarily intuitive to the average modern day trained pilot. The brake setup of a small application of differential braking at full rudder deflection can save the day and has. As speed decreases during the roll, vulnerability to loss of directional control increases.

Meanwhile, the Finch is subject to serious overcontrolling leading to accidents. The rudder cables were originally attached directly onto the tailwheel fork itself which lead to many overcontrol accidents. During the war, modifications or at least a study about them was made leading to some present day aircraft having a modified tailwheel strut where the cable attachment points are now fitted to a bracket that has been attached to the strut. The result is less tailwheel movement for a given amount of rudder input, although it is still very effective. As well, at touchdown on the Finch, it appears that main gear compression can happen at slightly different times leading to a temporary small heading change which can be over-compensated for and therefore lead to directional instability. While I have not personally experienced it on my few pavement landings, it has been suggested by another pilot to more plop it on in order to compress both struts right away and equally than feather it on and let struts settle on their own individual time. Higher tire pressure may also have a detrimental effect but this has just been talk.

In the end, one feels that there is much better response available for crosswind conditions in the Finch, especially at low speed due to its very effective rudder and very effective tailwheel. Finch ailerons are much more effective on the ground as well, as the Tiger Moth ailerons have the unusual feature of deflecting down a bit and then back to neutral as full stick deflection is reached. Mind you, your legs block full stick deflection anyways, strangely to your benefit as you have your little bit of down aileron(and lots of up aileron).

My personal preference for both types and most conventional gear aircraft is wheel landings on pavement and three-point on grass. But that is subject for endless debate among the many experts.

For the modern owner, you will find much more support and information about your Tiger Moth as there are so many of them. There is more than one type club around with excellent information, incredible regular magazines and books written(try finding anything on the Finch). Much of the Finch history has disappeared and the one club is much smaller and has few enthusiastic members although more are eagerly welcomed. Parts will likely be easier to find on the Tiger and there actually are original drawings for the Tiger unlike the disappeared Finch drawings.

Last edited by JammedStab; 26th Sep 2016 at 05:02.
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