Look at 3:40
I have never heard of this happening on a plane landing on the ground.
Looks to me like that pilot was lucky not to have suffered engine bearer failure at a less convenient moment.
Sure, the landing was poorly executed but no way should it result in engine bearer failure like that. I don’t think seaplane is relevant.
The short answer is no they don’t. Some seaplanes have many modifications fitted to make them seaplanes. Some like the Piper Cub and Beaver have little to none. Here are the differences in a seaplane 172N for example.
- Double skins at various fuselage points
- V Brace in the windshield
- Stainless Steel Control Cables
- Flaps limited to 30 degrees
- Rudder aileron interconnect
- Modification to fuel drains
- Change of propeller
- Different Engine Cowling
- Different Pitot Tube
- Four lifting rings on the roof
- Refuelling steps
- Placarding
- Water Ruddle Handle Install
All care of the seaplane bible, Seaplane Operations by Dale De Remer and Cesare Baj.
Stickandrudderman wrote:
Looks to me like that pilot was lucky not to have suffered engine bearer failure at a less convenient moment
Indeed. Would be interesting to see what exactly caused the weakening.
The Rudder – Aileron interconnect isn’t part of every Mod, I have flown a 172P amphib without. Actually, it would be counter-productive to seaplane ops on water.
The Pitot tube was standard heated, but I think the old tubes might be exchanged to heated ones.
As to the loads, seaplane float structures are very stiff. Hard landings do have a bigger effect on the loads due to higher shock transmissibility. That said, word has it, that it was a murphy rebel with an engine upgrade not substantiated by engineering data and/or tests. Something that will not happen so easy on todays certified STCs or with our certification processes.
It may well be induced by impact on water with a high sinkrate.
Not sure but probably the same will happen on a SEP land after such landing?
Ibra wrote:
Not sure but probably the same will happen on a SEP land after such landing?
No, because you have much more damping through the landing gear. Seaplanes are rigged very stiff and there is not much damping. A normal SEP would probably have a collapsed landing gear, first. Or, if you fly a taildragger, you will go drilling for petroleum.
Will not try it but yes I would expect a 50ft bounce or gear collapse not an “engine landing”
Stronger engine mounts are a desirable change for many Cessnas, the original mount just was not up to the prolonged shock loading of rough water. Wheel landing gear always has some shock absorbing capability, floats have none. Yes, water is fluid, but it is not soft! I’ve seen Cessna 180 “light” mounts cracked all over. Seaplanes West (now Acorn Welding) is one manufacturer of heavy engine mounts for Cessna, and they are very desirable.
Beyond that, the firewall back of tricycle 100 series Cessnas is really not designed to carry the floatplane loads. The early floatplane conversion STC’s of 182’s were poor, and I spent lots of labour repairing the firewall and belly skins of 182’s with floatplane conversions. I designed and approved an improvement. Later conversion kits were better, lessons learned. The Cessna 170/180/185 have the float forward attachments to “pork chops” which replaced the gear legs in their fittings. They could handle the loads. The tricycle 100 series Cessnas, when float converted, take the front float fittings to the lower engine mounts on the firewall. Those fittings are designed to pull the fuselage through the air, they are not designed to resist pushing up loads = wrinkled firewall. There are doublers, which help, but in hard service, they really don’t distribute the loads far enough into the forward fuselage. When I rebuilt an early 182 for floats, I installed thicker skins all the way around forward of the doorposts, and the doublers – that worked.
The V brace on Cessnas is an abomination. Unless a robust doubler is riveted up into the glareshield, the V brace tends to tear itself out. The glareshield was never designed to carry those shear loads over a long period. Much better are the cross bracing wires, as they go directly from the forward wing attachment hardpoint, to the opposing top engine mount hardpoint, through the glareshield, but not connected to it. I’ve felt a bracing wire go noticeably slack, when holding on to it as a passenger, and hitting a wave- those cables are working hard. They perform a very similar function to the cross bracing cables between the float struts. I had a damaged float cross bracing cable (actually a rolled airfoil section wire) break in flight. I landed really delicately. The plane settled low on one side, but the struts held. I had to perform some innovative field (well, lake shore) repairs to get it home.
If float Cessnas are operated from 6" or calmer waves, they’ll last well, but when they are pounded on 12"+ waves, they don’t last long at all!
