Thorp Air Command - T18.net

Out of curiosity, what would be the consensus about flying a T-18 without the canopy?

Only if it separated inflight and you then land at the closest avaialbe landing spot.

I have flown w/ the canopy open a couple inches for taking pictures. There was no turbulence in the cockpit and the canopy still wanted to pull forward.

Flying with the canopy open to "take Pictures" would not be something that would appeal to me. If the canopy were to suddenly depart the airplane, then you would have an immediate wind storm in the cockpit. Secondly, there is the risk that the canopy would impact the vertical fin or the horizontal stab...So far no one whose canopy has departed (to my knowledge) has impacted the tail.

_________________
Tom Hunter
805-202-4261

Agreed that a canopy departing in flight could be hazardous. However the canopy will naturally pull forward to a point. I do not know how far back this will occur but at 2" the force pulling forward is very strong.

Also if I'm not mistaken the Thorp T-18 was originally designed as open cockpit.

Correct you are...it was in fact designed as an open cockpit plane...HOWEVER...the fuselage behind the cockpit was different than the current configuration. The fuselage was what is commonly referred to as a "high back". The profile of the fuselage of the high back being high behind the pilot prevented the airflow from bashing into the back of the pilot. With a canopy on the plane, there is no such obstacle to the airflow hence. The shape of the fuselage was changed by the designer to accommodate the addition of the sliding canopy, other wise the canopy would have had to be along the lines of a FW-109.

The canopy frame of the T-18 is very light weight and relies on the plastic canopy to provide the rigidity of shape. Further, the canopy is one of the hardest items on the plane to fit (I spent 3 months)and is a fairly costly item. And the plans canopy latch while simple in design is time consuming to install..but I like it since it provides a satisfying solid feel when you turn the handle and latch ...all those factors influence me to do all I can to NEVER have to go back and install a new canopy.

The canopy on the Thorp is not designed to be open in flight. Yes, there is forward pressure on the canopy while the plane is moving. Anyone who has taxied their Thorp knows that the canopy want to close.
But in flight the air forces are very high on this light weight flexible item...if it starts to twist when in an open position, there is little rigidity in the structure to hold its shape. If one of the forward rollers slips its track or comes loose the canopy is gone in the blink of an eye. If you are wearing glasses, they may follow the canopy.

Not a pretty thought and one I would hope to avoid.

_________________
Tom Hunter
805-202-4261

Thanks for the information. I have taken the canopy apart and it is really is flimsy. I agree opening a canopy is a hazardous thing to do and mark it a thing not to do unless I'm about to ditch.

Tom is right...think of the canopy as Synergy. 2 or more parts working together to produce a result not obtainable by any of the parts independently. 1 + 1 = 3. [:p]

No I am not a lawyer, but I did stay at a Holiday Inn Express last nite ! [:0]

RB
NX115RX