What would happen if a person took a tamerlane or other target bow 69-72 inches and cut the recurve portion of the limbs off and make basically a longbow . Glue tip overlays on but string grooves etc . How much draw weight gain . Would performance be terrible or ???
Not to ruin a good bow but one that has problems at the limb tips .

You would have a super heavy bow that shoots like crap.

If the tip is beyond repair and makes the bow junk, why not try it! Narrow the limbs evenly to help bring the weight down.

Sounds like an experiment I would try.

Prolly a waste of time.

Yep a waste of time . High weight and stack bad. Hang it on the wall.

  I think there is a possibility that you can do something with it... 

How much would you have to take off the limbs to get past the damage??  How long are the limbs, the tip of the fade to the nock??  How long is your draw?? What is the draw weight of the bow?? What is the highest weight you are comfortable drawing??

Sound like a good idea if you are looking to do a crossbow build. 

A 68" Tamerlane riser is 30" from tip to tip of the fades, and 19" to the nocks. Aside from ruining one of the most beautiful old bows built (IMO), you would not end up with anything realistic.  Depends on how much tip you have to remove, I suppose. 1" - 1 1/2" might be ok? After that, maybe you could enter it in the flight distance shoot?

Halfdan maybe post some pics? What exactly are wrong wih the tips?

  It's a question out of curiosity.  I agree  wouldn't cut up a good functional bow .