Hi
I think this is the correct section of the forum, but feel free to move it
I have launched both small model rockets and high altitude weather balloons and I have researched combining the two It is definitely possible however there does not seem to be any consistent information regarding the effect that it will have on the rocket. Many sources state that the different is marginal, however even though they are talking about model rockets they seem to get caught up in reduction of orbit speed. obviously with a model rocket I would not be looking for reductions in the amount of orbit speed but reductions in amount of drag and therefore an increase in altitude. I found what I can only presume to be a reputable source on the subject - NASA's Proposal for a Balloon Assisted Launch System. It also was based on reaching LEO but it stated that: "A simple calculation using MATLAB that compared a launch from 120,000 ft with a ground launch suggested that a 25% decrease in required propellant mass was possible with a high-altitude launch system."
As this was for LEO orbit where the drag would of been reduced, but the delta v would of barely been reduced, meaning that for a straight up launch rathe than a launch aiming to orbit, surely there will be a larger decrease in the amount of propellant required. Would it be fair to assume that for a standard straight up launch, you would see a decrease of at least 35% in the propellant required as the atmosphere is 99% thinner? Therefore would the rocket theoretically have an altitude increase of roughly 35%? Obviously there would be no cost saving of this type of method and I would only be doing it for the challenge of it
To conclude, would a 35% altitude increase be a fair assumption?
I think this is the correct section of the forum, but feel free to move it
I have launched both small model rockets and high altitude weather balloons and I have researched combining the two It is definitely possible however there does not seem to be any consistent information regarding the effect that it will have on the rocket. Many sources state that the different is marginal, however even though they are talking about model rockets they seem to get caught up in reduction of orbit speed. obviously with a model rocket I would not be looking for reductions in the amount of orbit speed but reductions in amount of drag and therefore an increase in altitude. I found what I can only presume to be a reputable source on the subject - NASA's Proposal for a Balloon Assisted Launch System. It also was based on reaching LEO but it stated that: "A simple calculation using MATLAB that compared a launch from 120,000 ft with a ground launch suggested that a 25% decrease in required propellant mass was possible with a high-altitude launch system."
As this was for LEO orbit where the drag would of been reduced, but the delta v would of barely been reduced, meaning that for a straight up launch rathe than a launch aiming to orbit, surely there will be a larger decrease in the amount of propellant required. Would it be fair to assume that for a standard straight up launch, you would see a decrease of at least 35% in the propellant required as the atmosphere is 99% thinner? Therefore would the rocket theoretically have an altitude increase of roughly 35%? Obviously there would be no cost saving of this type of method and I would only be doing it for the challenge of it
To conclude, would a 35% altitude increase be a fair assumption?